He carried the thought further. The shadow had gotten upset because he and Scotty had gone swimming in an area where something was hidden. At least, that was a reasonable a.s.sumption, based on the events at St.

Thomas. The fancy diving gear in the house, the attempt to warn them off, and the presence of Steve's erstwhile shadow on Clipper Cay could then be added up.

Right here, in this particular area, another mysterious something was hidden! Something that the fancy frogmen dived often to see, use, collect, or whatever they did with it. That would account for their familiarity with the currents!

He started to tell Tony, then reconsidered. It was a pretty good hypothesis, he thought, but not supported by ironclad evidence. If he told the scientists, they might forbid any more diving in the area. And he was determined to get that treasure--more for his sister Barby than for himself. If he failed to get it there would be no living with Barby, since she would always maintain _she_ could have found it if they had only allowed her to go on their old expedition.

Zircon and Scotty broke water and Rick helped them aboard.

"It's a ship, and a sailing ship at that," Zircon boomed. "We identified what was almost certainly a compa.s.s binnacle, probably bra.s.s, but there wasn't time to get it free and bring it up. Scotty found what is probably the muzzle of a cannon, buried in the sand."

"There's so much growth over everything that it's hard to tell what's what," Scotty added. "But it certainly looked like a cannon muzzle."

"From what we saw, I suspect that the portion above the sand is the stern, probably the stern super-structure. If the timbers haven't completely rotted away, ripping off the top should expose the stern cabins."

"That seems reasonable," Tony agreed. "At any rate, it's a good basis for operation. Rick, if you'll look in my kit, you will find a larger bar you can borrow. You'll both need tools if you're going to take the ship apart."

"Anyway, that's enough diving for the morning," Zircon said. "Let's up anchor and go."

While the others got the boat underway, Rick started the compressor in the c.o.c.kpit and connected up the tanks they had used. He almost wished he and Scotty had been extravagant and had ordered triple tank blocks to give them maximum time under water. Still, the singles were convenient, and diving was a sport it wasn't wise to overdo. By the time they were through with lunch and had rested awhile, the tanks would be fully charged again.

As they tied up, Zircon said, "Tony and I will work at his midden this afternoon. You two take the boat. We won't need it. I'll walk over and take a look every once in a while, and if we see our friends from the cottage near you, we'll come running."

The boys helped Tony prepare a simple lunch of soup and sandwiches, then all hands retired to the front porch to eat.

Up the beach, there were signs of activity around the frogmen's boat. As they ate and watched, the boat moved away from the pier and approached the reef, where it anch.o.r.ed. Rick went to get the binoculars and focused them on the scene.

Two frogmen, complete with suits, went over the side right where their buoys floated!

"They're diving at the wreck!" he exclaimed.

Zircon took the gla.s.ses and watched, then handed them to Tony.

The archaeologist muttered, "Surely they can't be interested in the treasure. It would be simply too much coincidence for them even to know about it."

"Maybe they're just looking to see what interested us," Scotty offered, and his explanation seemed the most plausible.

The group watched until the frogmen surfaced and the boat went back to its pier.

"Scotty has it," Zircon agreed. "From what we've seen, I'd say they simply followed our buoy lines down to see what we had been doing."

"If that's the extent of their interest, I don't see how we could object," Tony said. "Or even if they tried for the treasure we'd have no grounds for objecting. The ship is anyone's property after all these years."

Rick said flatly, "We won't do any objecting, but we'll do plenty of watching. We're going to get that treasure if it's there, whether the fancy frogmen like it or not!"

CHAPTER X

The Wailing Octopus

As Rick steered the _Water Witch_ to its anchorage above the reef, he told Scotty about the theory he had developed that morning.

He concluded, "Their going out to take a look where we were diving is another piece of evidence. Unless they were afraid that we might be interested in their stuff--whatever and wherever it is--why would they be so concerned about what we're doing?"

"It makes a lot of sense," Scotty agreed soberly. He looked at Rick with a sudden twinkle. "It might be a good idea to take a look around down below--just so we'll know what to stay away from, of course."

Rick grinned.

By the time they dropped anchor, Scotty had the diving gear rigged and it was only the work of minutes to get into the water. Each carried a spear gun in one hand and a wrecking bar in the other. Ordinarily they would not have bothered with the guns, but being armed seemed just common sense.

On the bottom, Rick scouted around the wreck, looking for signs of its former structure while Scotty attacked the stern with a crowbar. Under Scotty's prying, a timber suddenly gave with an audible crack, and a huge grouper that must have weighed nearly three hundred pounds rushed past Rick, startling him half to death until he saw what it was.

Scotty hooted in derision as Rick back-pedaled, then he put his bar down and swam to Rick's side. He scrawled on his belt slate, "Whre he cm frm?"

Rick shrugged. It was a good question. They swam slowly around, looking for the grouper's hiding place and failed to locate it. Rick knew the big fish liked caves, rocky clefts, and the interiors of wrecks. This one must have a hole somewhere.

He tried again, going right down to the bottom and crawling along with stomach touching the sand. Even so, he might have missed the hole if stirred-up dust from the fish's sudden departure hadn't indicated where it was. The hole, big enough for him to crawl through, was _under_ the wreck, hidden by rotted planks covered with marine growth. He hooted for Scotty's attention and showed it to him.

He took his belt slate and wrote, "Way into shp?"

Scotty nodded and wrote in his turn, "Too drk. Need lites."

Rick nodded. For a moment he was tempted to try ripping off the planks with his bar, but he decided against it. Any disturbance might very well collapse the entire structure. He wondered whether the hole was just a shallow opening, or whether it actually led into the ship. No matter.

They had watertight flashlights with their spare gear in the boat. They could find out on the next dive.

For their remaining time underwater he joined Scotty in his a.s.sault on the stern of the ship. They were rewarded by finding what was evidently the interior of a cabin. Rick ripped off another plank, then jumped as Scotty hooted four times for danger. The cabin was the home of a fairly large moray eel! Both boys dropped their bars and grabbed for their spear guns, but Scotty held up his hand in a sign to wait. Rick did so, and saw the big eel emerge and swim rapidly toward the reef.

Scotty had shown wisdom. The moray is hard to kill, and this one would have given them a battle that might have used up more air than they could spare.

The water inside the cabin was murky. Rick looked at his watch. They had only a few minutes left. He wrote on his slate, "Sty dwn til rsrve wrning."

Scotty nodded agreement.

They watched as the water settled and the interior of the cabin grew clearer. Evidently it had been a very small cabin. There was a rotted frame that might once have been a single bunk, and a few broken, almost disintegrated boards that might have been a table. Mattress and bedding had long since vanished. Then Rick spotted a squarish shape under the ruin of the bunk and motioned to Scotty. They went in after it.

The top crumbled under their touch and silt rose into the water around them. But Rick persisted and felt fabric under his hands. He pulled it out and recognized a seaman's jacket, bra.s.s b.u.t.tons corroded and fabric nearly rotted through. Apparently they had found a sea chest, but their exploring hands discovered nothing but rotted fabrics.

Rick felt the warning constriction that told him he had only minutes left. He pulled down the reserve lever of his tank and touched Scotty's arm. He hooted twice for the ascent.

Back in the _Water Witch_, they connected their tanks to the compressor, put the regulators on charged tanks, then tested their underwater flashlights.

Rick said, "Do you realize I haven't taken a single picture?"

"Why not take some on the next dive?"

"Good idea." Rick went into the cabin and brought out his camera.