"One iron-clamped, sealed case. The stencil marks, although partly obliterated, appear to be D.O.C. in a circle; the impress on the seals to attached tracing. Contents"-Bethune paused and looked steadily at Clay-"I dare say you know what these are?"

"Do you?" Clay asked sharply.

"We opened the case."

There was silence for a few moments and all were very still. Clay's voice was not so steady when he spoke again.

"Where is the case?"

"Not here," said Bethune dryly. "If we don't turn up to claim it within a fixed time, or if any attempt is made to obtain possession of it in our absence it will be handed to the underwriters."

"You seem to have taken precautions," Clay remarked.

"We did the best we could," Bethune admitted with a modest air.

"Imagining that you might sell the box to me?"

"No!" Jimmy interposed sternly. "That was not our plan. When my partner first let you make an offer for the wreck-"

Clay stopped him with a gesture.

"It was to lead me on-you needn't explain. Very well; I suggested putting our cards down, and now I'll tell you something you don't suspect. There's a duplicate of that box on board and it contains the gold."

Jimmy started, Moran gazed at Clay with knitted brows, and Bethune looked frankly puzzled. Clay seemed quietly amused at their surprise.

"You don't understand?" he said. "After all, there's no reason why you should do so; but the truth of my statement is easily tested. Now I'll ask you a question to which I want a straight answer. What are you going to do with the gold you get?"

"Deliver it to the underwriters and claim salvage," said Jimmy promptly.

"That's all? You have no other plans?"

"That is all."

"Then I'll exchange the case which holds the gold for the one you have.

You can't recover it without my help."

For a time no one spoke. The three partners looked at one another in perplexed indecision, while Clay sat quietly still. There was a mystery behind the matter to which they could find no clue, and Clay would obviously not supply it. They did not know what to think.

"Do you know where to find this case?" Bethune asked.

"I believe so. I suggest that one of you come down to help me; Mr.

Farquhar for preference."

"Then you think of going down!" Jimmy exclaimed.

"I am going down the first thing to-morrow, whether you come or not. But what about my offer?"

"We can't answer yet," said Bethune. "It needs some thought."

"Very well," Clay agreed. "For all that, I must make a start in the morning. If you prefer, we can let the matter stand over until we find the case." He paused and smiled at Jimmy. "You don't look a nervous man and you needn't hesitate. I've never put on a diving dress and you have had some experience; and I'm willing to use your boat and let your friends control the pumps."

"I'm not afraid," retorted Jimmy. "The difficulty is that the way into the strong-room is not yet open. It will take at least a day to remove the sand that has banked up against the opening."

"Then I suppose I must wait, but I'll send my diver across to help you at daybreak," said Clay. "When everything is ready you can let me know.

Now, if you have no suggestion to make, I think I'll get back."

Moran signaled to the boat's crew, and when Clay had gone they sat down again in the cabin with thoughtful faces.

"I'll admit that things have taken an unexpected turn," Bethune remarked. "It's obvious that we're on the track of a secret of some importance which might explain a cunning fraud, but the matter's complicated by the shipping of the genuine box of gold, and I can't determine yet how far it's our business to investigate it."

"You don't seem so ready at forming theories as usual," Jimmy commented.

"I've made one or two and they look rather plausible until you test them. However, as it might be dangerous to jump to conclusions about the course we ought to take, I think we'd better wait. And now, as we're to start at daybreak, it might be wise to go to sleep."

CHAPTER XXIX-THE HIDDEN GOLD

The breeze was light at daybreak, and while the island still loomed shapeless and shadowy across the leaden water the yacht's gig brought Clay's diver and an excellent set of pumps. As soon as they were rigged the diver and Moran went below and took their turn with the others during the first half of the day, for there was still a good deal to be done before they could clear a pa.s.sage into the hold. They sent Clay word of their progress and at noon Aynsley was rowed across to the sloop.

"Although you refused last night, I hope you'll come on board to lunch,"

he said, after greeting them pleasantly.

"We have too much on hand," Jimmy replied. "In fact, we're not going to stop for a meal. It's unusually fine weather and we must get into the strong-room before dark. I expect it will take us three or four hours yet."

"It's a good excuse," returned Aynsley. "In a way, I'm glad you're too busy to come, because I imagine my father is very keen on finishing the job, and I don't want him to get worrying about the delay." He paused, and added frankly: "I'm going to ask a favor. He's not well, and I gather that you and he are to some extent opposed. Now I can't expect you to sacrifice your interest, but you might try to avoid any heated dispute as far as possible. Excitement isn't good for him."

"We can promise that," said Jimmy. "It looks as if you knew nothing about the business."

"I don't. And, more than that, I have no wish to learn anything."

"We're not in a position to tell you much if you pressed us; but it struck us that your father wasn't looking very fit, and it might be better if you stopped him from going down."

"I can't," Aynsley answered with a smile. "I'm afraid I haven't much control over him."

Early in the evening Clay came on board and sat in the c.o.c.kpit while the men relieved each other below. He asked a question now and then, but for the most part waited quietly, watching the bubbles that rose in milky effervescence.

At last the diver came up, and was followed closely by Bethune, bringing a rope.

"The strong-room's open," he said exultantly. "Heave on that line and see what you get!"

Moran pulled with a will, for there was some resistance to be overcome, and Jimmy leaned down in strong excitement when a wooden case smeared with sand broke the surface. Seizing it he came near to being dragged over the rail, and Bethune had to help him to lift it on board. Clay examined the case coolly, studying the half-washed-out marks.

"You ought to get something handsome for salvage on that, and I won't contest your claim," he said. "Keep it on board if you like; our diver's paid by the day. Now, if you're ready, we'll go down."

They carefully fastened on his dress, but when Bethune gave him a few instructions he said his own man had told him all he needed to know during the voyage. Jimmy put on his helmet and went first down the ladder, waiting at the bottom for Clay. It was, he felt, a strange experience to be walking along the sea-floor with a man who had been his enemy; but he was now master of the situation. Indeed, he had to help his companion when they reached the entrance to the hold and he did not think that Clay could have crept up the dark pa.s.sage between the shaft tunnel and the hanging weed on the ship's crushed side without his a.s.sistance. Their lamps glimmered feebly through the water that sucked in and out, and it was no easy matter to keep signal-lines and air-pipes clear. Clay, however, though awkward and somewhat feeble in his movements, showed no want of nerve.