Notable discovery at the spouting cliffs—The mysterious green monster explained—We are thrown into unutterable terror by the idea that Jack is drowned—The Diamond Cave.

"Well," answered Jack, throwing down the axe with which he was just about to proceed towards the boat, "if that's what you want, I would recommend you to make an excursion to the water-spouts. The last one we had to do with tossed you up a considerable height; perhaps the next will send you higher—who knows?—if you're at all reasonable or moderate in your expectations!"

"Jack, my dear boy," said Peterkin gravely, "you are really becoming too fond of jesting. It's a thing I don't at all approve of, and if you don't give it up, I fear that, for our mutual good, we shall have to part."

"Well then, Peterkin," replied Jack with a smile, "what would you have?"

"Have?" said Peterkin; "I would have  nothing. I didn't say I wanted to have;  I said that I wanted to do."

"By-the-bye," said I, interrupting their conversation, "I am reminded by this that we have not yet discovered the nature of yon curious appearance that we saw near the water-spouts, on our journey round the island. Perhaps it would be well to go for that purpose."

"Humph!" ejaculated Peterkin, "I know the nature of it well enough."

"What was it?" said I.

"It was of a mysterious  nature to be sure!" said he, with a wave of his hand, while he rose from the log on which he had been sitting and buckled on his belt, into which he thrust his enormous club.

"Well, then, let us away to the water-spouts," cried Jack, going up to the bower for his bow and arrows; "and bring your spear, Peterkin. It may be useful."

We now, having made up our minds to examine into this matter, sallied forth eagerly in the direction of the water-spout rocks, which, as I have before mentioned, were not far from our present place of abode. On arriving there we hastened down to the edge of the rocks and gazed over into the sea, where we observed the pale-green object still distinctly visible, moving its tail slowly to and fro in the water.

"Most remarkable!" said Jack.

"Exceedingly curious!" said I.

"Beats everything!" said Peterkin.

"Now, Jack," he added, "you made such a poor figure in your last attempt to stick that object, that I would advise you to let me try it. If it has got a heart at all, I'll engage to send my spear right through the core of it; if it hasn't got a heart, I'll send it through the spot where its heart ought to be."

"Fire away then, my boy," replied Jack with a laugh.

Peterkin immediately took the spear, poised it for a second or two above his head, then darted it like an arrow into the sea. Down it went straight into the centre of the green object, passed quite through it, and came up immediately afterwards, pure and unsullied, while the mysterious tail moved quietly as before!

"Now," said Peterkin gravely, "that brute is a heartless monster; I'll have nothing more to do with it."

"I'm pretty sure now," said Jack, "that it is merely a phosphoric light; but I must say, I'm puzzled at its staying always in that exact spot."

I also was much puzzled, and inclined to think with Jack that it must be phosphoric light, of which luminous appearance we had seen much while on our voyage to these seas. "But," said I, "there is nothing to hinder us from diving down to it, now that we are sure it is not a shark."

"True," returned Jack, stripping off his clothes; "I'll go down, Ralph, as I'm better at diving than you are.—Now then, Peterkin, out o' the road!" Jack stepped forward, joined his hands above his head, bent over the rocks, and plunged into the sea. For a second or two the spray caused by his dive hid him from view; then the water became still, and we saw him swimming far down in the midst of the green object. Suddenly he sank below it, and vanished altogether from our sight! We gazed anxiously down at the spot where he had disappeared for nearly a minute, expecting every moment to see him rise again for breath; but fully a minute appeared, and still he did not reappear. Two minutes passed! and then a flood of alarm rushed in upon my soul, when I considered that, during all my acquaintance with him, Jack had never stayed under water more than a minute at a time; indeed, seldom so long.

"O Peterkin!" I said, in a voice that trembled with increasing anxiety, "something has happened. It is more than three minutes now." But Peterkin did not answer, and I observed that he was gazing down into the water with a look of intense fear mingled with anxiety, while his face was overspread with a deadly paleness. Suddenly he sprang to his feet and rushed about in a frantic state, wringing his hands, and exclaiming, "O Jack, Jack! he is gone! It must have been a shark, and he is gone for ever!"

For the next five minutes I know not what I did; the intensity of my feelings almost bereft me of my senses. But I was recalled to myself by Peterkin seizing me by the shoulders and staring wildly into my face, while he exclaimed, "Ralph! Ralph! perhaps he has only fainted. Dive for him, Ralph!"

It seemed strange that this did not occur to me sooner. In a moment I rushed to the edge off the rocks, and without waiting to throw off my garments, was on the point to spring into the waves, when I observed something black rising up through the green object. In another moment Jack's head rose to the surface, and he gave a wild shout, flinging back the spray from his locks, as was his wont after a dive. Now we were almost as much amazed at seeing him reappear, well and strong, as we had been at first at his non-appearance; for, to the best of our judgment, he had been nearly ten minutes under water, perhaps longer, and it required no exertion of our reason to convince us that this was utterly impossible for mortal man to do and retain his strength and 118 faculties. It was therefore with a feeling akin to superstitious awe that I held down my hand and assisted him to clamber up the steep rocks. But no such feeling affected Peterkin. No sooner did Jack gain the rocks and seat himself on one, panting for breath, than he threw his arms round his neck and burst into a flood of tears. "O Jack, Jack!" said he, "where were you? What kept you so long?"

After a few moments Peterkin became composed enough to sit still and listen to Jack's explanation, although he could not restrain himself from attempting to wink every two minutes at me, in order to express his joy at Jack's safety. I say he attempted to wink, but I am bound to add that he did not succeed, for his eyes were so much swollen with weeping, that his frequent attempts only resulted in a series of violent and altogether idiotical contortions of the face, that were very far from expressing what he intended. However, I knew what the poor fellow meant by it, so I smiled to him in return, and endeavoured to make believe that he was winking.

"Now, lads," said Jack, when we were composed enough to listen to him, "yon green object is not a shark; it is a stream of light issuing from a cave in the rocks. Just after I made my dive, I observed that this light came from the side of the rock above which we are now sitting; so I struck out for it, and saw an opening into some place or other that appeared to be luminous within. For one instant I paused to think whether I ought to venture. Then I made up my mind, and dashed into it. For you see, Peterkin, although I take some time to tell this, it happened in the space of a few seconds, so that I knew I had wind enough in me to serve to bring me out o' the hole and up to the surface again. Well, I was just on the point of turning—for I began to feel a little uncomfortable in such a place—when it seemed to me as if there was a faint light right above me. I darted upwards, and found my head out of water. This relieved me greatly, for I now felt that I could take in air enough to enable me to return the way I came. Then it all at once occurred to me that I might not be able to find the way out again; but, on glancing downwards, my mind was put quite at rest by seeing the green light below me streaming into the cave, just like the light that we had seen streaming out of it, only what I now saw was much brighter.

"At first I could scarcely see anything as I gazed around me, it was so dark; but gradually my eyes became accustomed to it, and I found that I was in a huge cave, part of the walls of which I observed on each side of me. The ceiling just above me was also visible, and I fancied that I could perceive beautiful glittering objects there; but the farther end of the cave was shrouded in darkness. While I was looking around me in great wonder, it came into my head that you two would think I was drowned; so I plunged down through the passage again in a great hurry, rose to the surface, and—here I am!"

When Jack concluded his recital of what he had seen in this remarkable cave, I could not rest satisfied till I had dived down to see it: which I did, but found it so dark, as Jack had said, that I could scarcely see anything. When I returned, we had a long conversation about it, during which I observed that Peterkin had a most lugubrious expression on his countenance.

"What's the matter, Peterkin?" said I.

"The matter?" he replied. "It's all very well for you two to be talking away like mermaids about the wonders of this cave, but you know I must be content to hear about it, while you are enjoying yourselves down there like mad dolphins. It's really too bad."

"I'm very sorry for you, Peterkin, indeed I am," said Jack, "but we cannot help you. If you would only learn to dive—"

"Learn to fly, you might as well say!" retorted Peterkin in a very sulky tone.

"If you would only consent to keep still," said I, "we would take you down with us in ten seconds."

"Hum!" returned Peterkin; "suppose a salamander was to propose to you 'only to keep still,' and he would carry you through a blazing fire in a few seconds, what would you say?"

We both laughed and shook our heads, for it was evident that nothing was to be made of Peterkin in the water. But we could not rest satisfied till we had seen more of this cave; so, after further consultation, Jack and I determined to try if we could take down a torch with us, and set fire to it in the cavern. This we found to be an undertaking of no small difficulty, but we accomplished it at last by the following means: First, we made a torch of a very inflammable nature out of the bark of a certain tree, which we cut into strips, and, after twisting, cemented together with a kind of resin or gum, which we also obtained from another tree; neither of which trees, however, was known by name to Jack. This, when prepared, we wrapped up in a great number of plies of cocoa-nut cloth, so that we were confident it could not get wet during the short time it should be under water. Then we took a small piece of the tinder, which we had carefully treasured up lest we should require it, as before said, when the sun should fail us; also, we rolled up some dry grass and a few chips, which, with a little bow and drill, like those described before, we made into another bundle, and wrapped it up in cocoa-nut cloth. When all was ready, we laid aside our garments, with the exception of our trousers, which, as we did not know what rough scraping against the rocks we might be subjected to, we kept on.

Then we advanced to the edge of the rocks, Jack carrying one bundle, with the torch, I the other, with the things for producing fire.

"Now don't weary for us, Peterkin, should we be gone some time," said Jack; "we'll be sure to return in half-an-hour at the very latest, however interesting the cave should be, that we may relieve your mind."

"Farewell!" said Peterkin, coming up to us with a look of deep but pretended solemnity, while he shook hands and kissed each of us on the cheek. "Farewell! and while you are gone I shall repose my weary limbs under the shelter of this bush, and meditate on the changefulness of all things earthly, with special reference to the forsaken condition of a poor shipwrecked sailor boy!" So saying, Peterkin waved his hand, turned from us, and cast himself upon the ground with a look of melancholy resignation, which was so well feigned that I would have thought it genuine had he not accompanied it with a gentle wink. We both laughed, and springing from the rocks together, plunged head first into the sea.

We gained the interior of the submarine cave without difficulty, and, on emerging from the waves, supported ourselves for some time by treading water, while we held the two bundles above our heads. This we did in order to let our eyes become accustomed to the obscurity. Then, when we could see sufficiently, we swam to a shelving rock, and landed in safety. Having wrung the water from our trousers, and dried ourselves as well as we could under the circumstances, we proceeded to ignite the torch. This we accomplished without difficulty in a few minutes; and no sooner did it flare up than we were struck dumb with the wonderful objects that were revealed to our gaze. The roof of the cabin just above us seemed to be about ten feet high, but grew higher as it receded into the distance, until it was lost in darkness. It seemed to be made of coral, and was supported by massive columns of the same material. Immense icicles (as they appeared to us) hung from it in various places. These, however, were formed not of ice, but of a species of limestone, which seemed to flow in a liquid form towards the point of each, where it became solid. A good many drops fell, however, to the rock below, and these formed little cones, which rose to meet the points above. Some of them had already met, and thus we saw how the pillars were formed, which at first seemed to us as if they had been placed there by some human architect to support the roof. As we advanced farther in, we saw that the floor was composed of the same material as the pillars; and it presented the curious appearance of ripples such as are formed on water when gently ruffled by the wind. There were several openings on either hand in the walls that seemed to lead into other caverns; but, these we did not explore at this time. We also observed that the ceiling was curiously marked in many places, as if it were the fretwork of a noble cathedral; and the walls, as well as the roof, sparkled in the light of our torch, and threw back gleams and flashes as if they were covered with precious stones. Although we proceeded far into this cavern, we did not come to the end of it; and we were obliged to return more speedily than we would otherwise have done, as our torch was nearly expended. We did not observe any openings in the roof, or any indications of places light might enter; but near the entrance to the cavern stood an immense mass of pure white coral rock, which caught and threw back the little light that found an entrance through the cave's mouth, and thus produced, we conjectured, the pale-green object which had first attracted our attention. We concluded, also, that the reflecting power of this rock was that which gave forth the dim light that faintly illumined the first part of the cave.

Before diving through the passage again we extinguished the small piece of our torch that remained, and left it in a dry spot; conceiving that we might possibly stand in need of it, if at any future time we should chance to wet our torch while diving into the cavern. As we stood for a few minutes after it was out, waiting till our eyes became accustomed to the gloom, we could not help remarking the deep, intense stillness and the unutterable gloom of all around us; and, as I thought of the stupendous dome above, and the countless gems that had sparkled in the torchlight a few minutes before, it came into my mind to consider how strange it is that God should make such wonderful and exquisitely beautiful works never to be seen at all, except, indeed, by chance visitors such as ourselves.

I afterwards found that there were many such caverns among the islands of the South Seas, some of them larger and more beautiful than the one I have just described.

"Now, Ralph, are you ready?" said Jack, in a low voice, that seemed to echo up into the dome above.

"Quite ready."

"Come along, then," said he; and plunging off the ledge of the rock into the water, we dived through the narrow entrance. In a few seconds we were panting on the rocks above, and receiving the congratulations of our friend Peterkin.