The tide was very low, the sun up bright and high, and the water so clear that there was every rock below us so close that it seemed as if we could not go over some of them without touching.

"We'll row out to the buoyed grapnel," said Bigley; "make fast, and while you have your bathe I shall dive down, follow the rope, and see if I can find out how the grapnel has got fast."

"If you can," I said.

"Well, I'm going to try," replied Bigley. "I don't suppose it's above three fathoms deep."

"You can't dive down three fathoms?" I said.

"Can't I?" replied Bigley laughing. "I'm going to show you. Look here!"

He pointed to a big long stone in the bows of the boat weighing some twenty-pounds. To this a thin line was attached, and I saw his meaning at once.

"Yes," I said, "that will do it, only don't forget to let go."

"No fear," he replied; and we paddled on, with the beautiful view of the cliffs opening out as we rowed farther from the sh.o.r.e.

We had nearly a quarter of a mile to go before we struck against the floating boat-hook close to the now exposed rocks, when Bigley threw in his oar, hoisted the rough buoy aboard, unhitched the rope, ran it through the ring-bolt, and hauled on till he had the boat's stem right over the grapnel, which still refused to come; so we made fast.

Bigley then began to undress rapidly, while I proceeded to work more slowly, being curious to watch what he was doing.

I had not long to wait, for after making fast one end of the thin line to the thwart of the boat he poised the stone on the gunwale, leaped in, and then putting his left arm round the grapnel rope he got well hold of the stone, and drew it over to descend with it rapidly to the bottom.

I crept to the bows and looked over to see his white body far below in the clear water, and then he came up again to rub his eyes, pant, and hold on by the side of the boat.

"Why, what's the matter?" I said; "seen a shark?"

"No," he cried, "but I've seen something else. Here, haul up the stone."

"Bother the stone!" I exclaimed, "I came to bathe."

"Haul it up quickly," he said; and I obeyed, and afterwards lifted it on to the gunwale.

He seemed very excited, but he would not speak about what he had seen, only beg me to do what he told me, which was to untie the line from the stone and then make a running noose and put it loosely round.

I did all this, wondering at his mysterious way, but only expecting that it was to fasten round the grapnel so as to pull in a fresh direction.

As soon as I had done he took hold of the loop that was round the stone, drew a long breath, and asked me to lift it over into the water.

This I did, and he went down head-first, while I again watched him below among the waving weeds all indistinct in the troubled sea.

He was down for a full minute as I crouched there with my head over the side. He seemed to be so long that I began to grow alarmed lest he had become entangled, and I was about to haul up the line attached to the stone. I looked down anxiously with my face closer to the surface, but only to make him out in a bleared indistinct manner, and then he shot up like a line of light and swam to the side and held on.

"Thought I shouldn't be able to do it," he said; "but I've got the line round."

"Well, what next?" I said. "But I say, is a grapnel worth all this trouble?"

"A grapnel?" he said with a peculiar smile.

"Yes."

"Wait a minute till I am in the boat."

He climbed in, and came to my side.

"Now," he said; "haul up steadily. I think she'll come."

I tightened the line, and for a moment or two there was a dead resistance. Then something heavy began to stir, and I hauled away steadily, hand over hand.

"I've got it," I said as I gazed down. "It was right in amongst some strong weed. Here it comes."

I pulled away till I had nearly got it to the top, and then Bigley came to my help, reached over, and the object I was dragging up b.u.mped against the boat, slipped out of the noose, and went down rapidly just like a ma.s.s of stone.

"What did you fasten the line to that for?" I said.

"What did I do it for, Sep?" he panted. "Didn't you see what it was?"

"No," I said bluntly.

"What did it look like?"

"Box covered with sea-weed," I replied.

"Well, don't you see now?"

"No," I replied.

"Why, Sep, how dull you are this morning!" he cried. "Didn't you see that you had hold of one of your father's silver chests?"

"_One of my father's what_?" I roared.

"One of the silver chests. Sep, it was over these rocks, against that one, I suppose," he cried, pointing to a huge block just below the surface, and a favourite haunt of conger, "that the Frenchman's boat capsized."

"What, the one with the silver?" I cried.

"Yes, and I believe all the chests are at the bottom there."

"And they were coming back to try for them when the frigate came in sight!" I shouted.

"Yes, yes, yes."

"Hurrah! Hurrah! Hurrah!" I cried, leaping up in the boat, and waving my arms about like an idiot. "Why, Bigley, it will set father free of all his troubles. Here, I'm half mad. What shall we do? Hold hard a moment: I'm going down to see."

I had only my breeches on, and tearing these off, I stepped on to the gunwale, leaped up, turned over, and dived down into the clear cold water, trying with all my might to reach the bottom, but only describing a curve, and coming up again about twenty feet from the boat.

I swam back to have another try, but Bigley stopped me as I was about to dive off.

"No, no," he said; "it's of no use. You can't get down there without a killick or some other weight."