Scotty added, "Today, when we got to the station, I took a look along the trail. There's only one bend in it. If he was keeping a watch at the bend, he could have seen us arrive at the second station, hurried down the trail, set off the charge, then returned through the jungle to get his jeep."

"But the fact that he could have, does not mean that he did," Hartson Brant stated.

"We can't prove it," Scotty agreed.

Rick continued. "Then we trailed him to Casa Guevara. He couldn't have been paying a social call, because he wasn't there long enough. And what business does he have with Guevara? I don't know, but I'll bet his business is the reason we can't get Guevara to move."

"Possibly," Hartson Brant agreed. "I can see the reason for your suspicions, but you lack proof of anything, Rick. What motive could Connel have?"

"We hoped to find out at the shot station," Rick replied. "But we drew a blank."

Dr. David Riddle came into the room and joined them. Before anyone could speak, the geologist spotted the samples on the table and sucked in his breath sharply.

"Where did these come from?" he demanded.

"Connel's third shot station," Rick replied. "Do you know what the stuff is?"

Riddle sank into a chair and picked up one of the samples, testing it between his fingers. "Yes," he said, "I do. I've seen it only once before, in Africa. It occurs in what is known as a volcanic pipe, actually an ancient channel that gets filled with the stuff for reasons we do not know."

"A volcanic pipe," Hartson Brant said softly. "I'm beginning to see."

Rick wasn't. "But what is it?" he asked.

"The most valuable kind of ground in the world," Riddle said. "So far as anyone knew up to now, such pipes have occurred only in Africa. The one I saw was at Kimberley. The name came from there. This is kimberlite."

[Ill.u.s.tration]

Rick knew of only one kind of valuable that was a.s.sociated with Kimberley, and the thought was so staggering that he was almost afraid to say it out loud. "You mean that this is the stuff diamonds are found in?"

"Exactly," Riddle said.

Rick fished the handful of crystals from his pocket and stared at them unbelievingly. "Then these," he said hoa.r.s.ely, "must be diamonds!"

CHAPTER XI

Earthquake!

"Everything adds up," Rick Brant said grimly. "And it isn't a pretty picture."

Hartson Brant agreed. "It certainly seems to add up, Rick. I suggest you put those crystals in a safe place until we can find out for certain whether or not there is real value there."

"Is there any doubt?" Scotty asked.

David Riddle answered, "Yes, Scotty. There are many grades of diamonds.

Until an expert takes a look at those Rick collected, we won't be sure that they're of gem quality. He may have industrial grade diamonds, of the type called bort."

"Connel may already have had an expert take a look," Weiss pointed out.

Rick examined the handful of crystals. It was hard to believe he had simply picked up diamonds like so many pebbles. What's more, he couldn't be sure whether he held a king's ransom in his hand or a few dollars'

worth of industrial abrasives.

"Why didn't Connel clean out all diamonds in the area?" he demanded.

"How could he?" Hartson Brant retorted. "When has he had time for a real effort? I suspect he has picked up quite a few, but you found those just by kicking around, which would indicate he hasn't sifted that loose ground very thoroughly."

David Riddle frowned. "It's odd that Rick found so many. Perhaps he was lucky enough to kick open a pocket that Connel missed. Diamonds just don't occur with such frequency, even in Kimberley."

"They were pretty close together," Rick remembered. "It may have been a pocket, all right."

"There is one other possibility," Riddle added, "and it's staggering to think of it. These crystals may have come from a single large crystal.

Perhaps the dynamite explosions shattered the big one into a number of smaller ones."

Scotty gulped. "But the original crystal would have had to be nearly the size of a grapefruit!"

"True, Scotty. There have been crystals that big, or close to it.

Usually the diamond that is cut from such a crystal is much smaller.

There is considerable loss. But it's a possibility."

Rick said abruptly, "I think we ought to sort of review the situation.

To see where we stand."

"A good idea," his father agreed. "Suppose you start?"

Rick considered. "Well, Connel must have discovered the yellow ground the very first thing, probably while he was kicking a hole to lay the charge in. The reason I think so is because of Ruiz. That accident has always bothered me. Ruiz just wouldn't walk back to the charge while Connel was ready to set it off. He just wouldn't."

Julius Weiss asked, "Are you implying that Connel deliberately blew Ruiz up?"

"What else can we make of it?" Rick replied. "That kind of accident just doesn't happen. Not to an expert. But if Connel found the yellow ground while setting the charge, and took time to dig a little and be sure there was blue ground under it, he would certainly have known that he was standing on top of a volcanic pipe. He might even have picked up a crystal."

"If word got out, he couldn't exploit the pipe," Scotty added. "So, Ruiz had to be eliminated. It would have been pretty easy. Connel had the watch. He could have kept track of the time, then asked Ruiz to make a final check and set the charge off while the poor guy was taking a look at the connections."

"It could have happened that way," Hartson Brant agreed. "But I hate to think any human being could be so ruthless."

"Connel had to keep others away, too," Rick went on. "Also, he had to slow things down so he could have time to set something up to exploit his find. So, he stole the tracings and the dynamite. That bought him a little time, didn't it? Then he tried to get Scotty and me, because we were following him and he was afraid we might find out what was going on."

"It seems reasonable," Hartson Brant agreed.

"Connel couldn't develop a diamond field in a foreign place without help, could he? He had to let someone in on it, locally. He sized up Guevara and figured the lieutenant governor could certainly help him out, so he brought Guevara in on it."

"Pure speculation," Weiss said.

"Yes, sir. But it fits. Guevara certainly wouldn't want people running around over there, so it's to his advantage to keep us from operating.

If he thinks there's a fortune in the pipe, it's even to his advantage to kidnap the governor to make sure we can't follow our plans!"

David Riddle shook his head. "A man would have to be insane to hold up an effort to save the island just to make himself rich."