THE bos'n's proposal was hailed with enthusiasm, for, curiously enough, neither my father nor my uncle had given any thought to the blasting powder the use of which is an everyday occurrence in the mining districts of Cornwall.

"How much of the stuff have we?" asked my father.

"Mr. Herbert had over fifty pounds of it carried ashore before the gale," replied the bos'n. "It's all in air-tight cases, so it won't be damaged by being buried."

"It's a wonder the whole lot hadn't exploded during the storm! There's enough rock brought down from the cliff to show that the shock was exceptionally severe, to say nothing of the chance of it being struck by lightning."

"But it hasn't, sir, so that is something to be thankful for. However, it would be well to finish unloading the ballast from the yacht, but not to take the silver aboard till we have blown up the rock and made a clear passage through."

"For what reason, Mr. Wilkins?"

"Simply because we don't know what depth the new cutting will be. It might be twelve feet, it might be only six; so the lighter we can make the vessel the less draught she'll draw, and the greater chance she'll have of slipping through."

"But there will be greater difficulty in loading up outside the reef."

"Granted, sir; but we must take the risk, unless, of course, the blasting-powder cuts a deep and unobstructed channel."

So, directly we returned to the "Fortuna," message was sent to the wreck to defer the removal of the pigs of silver for the present.

On my uncle's return he reported that the twenty sows were correct in number, but only ten chests full of pieces-of-eight were to be found, so it was assumed that the remaining five chests had been broken open and their contents shared out by Humphrey Trevena immediately after the capture of the "San Philipo" by the "Anne."

Nearly five tons of ballast had been removed from the "Fortuna," more than sufficient to compensate for the additional weight of the specie; but, in view of the probable difficulty of taking the yacht between the reefs to the open sea, it was decided to proceed with the unloading of the iron ballast, till the "Fortuna's" draught would be reduced to the least margin of safety.

"We've done very well this forenoon," remarked my father, "so we can reasonably take a spell off till the sun is low down."

"As you like, but, personally speaking, I have a perfect craving for hard work," replied Uncle Herbert, "so I'll beat up volunteers and recover the blasting powder."

"You won't bring it aboard?"

"No, I will take it off to the reef, close to the channel you mentioned."

"I'll go, too," I exclaimed, "for I want very much to have a look at the great cave that we can see from here."

"I don't think so," objected my uncle. "A boatload of explosives, powerful enough to blow, us to infinitesimal particles, is hardly a safe cargo, so you will be safer on board the 'Fortuna.'"

"I know, but you can take the stuff off to the reef and come back for me. It's only a ten minutes' pull, you know. Don't be hard on a fellow, uncle. It's the first time I've had a chance to go ashore in that part of the bay, and I want to explore the cave."

"Very well, then," replied my uncle ungraciously. "But mind, no monkey-tricks, and don't run into mischief."

I ran below to the bos'n's locker, where I abstracted a ball of seaming-twine and a couple of candles, and, putting these articles into my coat pocket in company with a box of matches, I went on deck and clambered into the gig.

The spot where the explosives had been buried was in a grove, a short distance from a little bay, which was enclosed on either hand by tall cliffs, and inaccessible from the rest of the lagoon except by means of a boat, unless a path was cut inland through the dense scrub, which apparently had never yet been penetrated by human beings.

The taller of the two cliffs was almost divided from base to summit by the curiously shaped cave which Old Humphrey had laid particular stress upon in his log, and directly the boat touched the sandy beach I bounded off towards it on my trip of exploration, a final warning from my uncle falling lightly upon my ears.

A heap of loose boulders, which had fallen during the shock, encumbered the mouth of the cave; but these I easily surmounted, and advanced cautiously over the smooth floor, my eyes dim by the sudden change from the brilliant sunshine to the subdued light of the cavern.

The walls were composed of blocks of basalt, the general regularity of the vertical shafts broken here and there by gaping horizontal and diagonal fissures, while at intervals a thin stream of water fell from the roof with a cool and pleasing sound.

As I proceeded the roof gradually became lower, till, just as the daylight failed, its height was less than twenty feet. Taking the ball of twine out of my pocket, I made fast one end to a projecting ledge. The candles, I found, had united into a soft bent stick of wax by reason of the heat of the sun, but, straightening them out and cooling them in a pool of water, I had a double-wicked torch in place of the two candles.

As I went on, making a careful survey of the ground for fear of pitfalls, I noticed that on either hand numerous side passages branched out, some large, some small; but, keeping as straight a direction as I could, I advanced slowly, paying out the twine as I went.

At length the smooth floor gave place to a ridge of rock, about four feet in height, leaving an opening of barely three feet between it and the roof. Here I stopped, debating with myself whether it would be wiser to retrace my way, but a feeling of uncontrollable curiosity urged me to continue my investigations.

Having unrolled a length of twine, I threw the ball over the barrier. Having one hand free, I began to clamber over the ridge, holding the lighted candle carefully in my left hand. Beyond I could see that the floor was even, though higher than on the side which I had left, so I unhesitatingly slipped down the opposite slope of the rock and gained the interior of the inner cave.

The light flickered on innumerable stalactites, which glittered like pinnacles and pendants of dazzling gems, while, for the first time, I became aware of the dismal silence and tomb-like solitude of the cave. I tried to whistle, but no sound came from my parched lips; then I called in a low tone, and to my surprise the echoes surpassed my voice in the volume of sound and then gradually died away, till it seemed as if, from the remote recesses of the cavern, came a mocking laugh.

I repeated the call, and again yet louder, when suddenly there was a rush and a roar, and I found myself lying on my back in utter darkness.

For some considerable time I lay helpless, the utter blackness and the terrifying solitude almost depriving me of my senses. Something heavy was gripping my left foot, and I found that I was held by a mass of fallen stone. The candle had been thrown from my hand, and was extinguished by the fall; but with feverish haste I drew the box of matches from my pocket and struck a light. Close at hand was the candle, and by its renewed light I saw, to my horror, that a fall had occurred from the roof, and my retreat was cut off by a tightly wedged mass of stone.

By a supreme effort I wrenched my foot free and staggered upright, stifling a desire to shout for fear that a further fall might occur. Hastily I tried to find a communication through the barrier, but there was no hope in that direction. Even the twine was held as firmly, as if tied to a post, and, on attempting to pull it, the thread broke off close to the rock.

I broke into a cold sweat, but after a few minutes I recovered my senses to a certain extent, arguing with myself that I should be missed before long, and that plenty of willing hands could remove that mass of rubble which held me prisoner.

The light, however, gave me grave misgivings, for the double-wicked candle was burning away rapidly, so, by the aid of my knife, I split the wax cylinder lengthways, thus giving me two candles, as I had original............