"Nothing new," Riddle reported. "The only sign of activity is a fresh outpouring of hydrogen sulfide. It's bubbling up through the mud, and it could be a pocket of gas that was suddenly released. The springs won't tell us much."

Hartson Brant said thoughtfully, "I'm afraid you're right, Dave.

Nothing for it but to keep shooting. And we'll lock up the papers at night, so we can keep track of what's going on. One thing we'd better do is start a survey of the entire cone, above the level where our shots give us information. I'd like to be sure we're not overlooking any new gaps or fissures in the mountain itself. But can we do it with the manpower we have available and still keep shooting?"

Rick spoke up. "I know how we can help, Dad. Scotty and I can handle our stations alone now. That will leave Dr. Zircon free for other things.

Then, if we change stations with Brad Connel, and he takes the closer ones, he can get back a good hour earlier and do other work."

"No!" Brad Connel exploded.

Hartson Brant and the other scientists looked at him with surprise. "Why not?" Dr. Brant asked. "It seems like a sensible suggestion, Brad."

"It is," Connel said hurriedly. "It's just that ... well, maybe I'm still too upset over that accident, but I know the terrain now, and these kids don't. They should stick to the stations where they've been operating, and I'll handle my own. It's just that I don't want any risks whatever. My own part of the mountain is a lot rougher, and they'd be carrying dynamite and caps over pretty bouncy trails. I don't like it. I think we should stick to our own stations."

The geologist obviously felt strongly about it, and Hartson Brant agreed. "Since you feel that way, Brad, we'll let things go as they are.

Hobart, can the boys handle the shots?"

"Sure," Zircon stated. "As long as Rick doesn't crimp caps with his teeth. Of course if he does we'll still get a reading, but we may lose Rick."

"No danger," Rick retorted. "Besides, you wouldn't get a reading because the shot wouldn't be timed right."

Hartson Brant saw that the big scientist was joking. "If Rick feels adventurous he can kick mountain lions for sport instead. I'm told there are some on the mountain."

"Jaguars," Dr. Balgos offered. "Not your typical North American cats.

These are much fiercer. They react faster to a kick--if you can get close enough to kick one."

Brad Connel laughed heartily. "The boys can lure 'em with catnip," he said.

Rick glanced at the geologist. The laugh hadn't rung true.

"I suggest we also save time by shooting in the early morning," Hartson Brant added. "That will leave the afternoon for other activities. Jeff, if you can manage to keep your head out of the way of blunt instruments, perhaps you'd like to make a better sketch of the magma front. We can a.s.sign the boys as guards, if you like."

Dr. Williams caressed the bruise on his head. "Not necessary, Hartson.

I'll lock my door and keep my face toward the window. But for now, how about dinner?"

There was no disagreement.

After dinner, Rick and Scotty lingered over coffee with Dr. Balgos, Julius Weiss, and Hartson Brant. The others had excused themselves and gone back to their rooms. The boys were trying to learn more about volcanoes, but the scientists had a tendency to get involved in discussions of some of the finer points of geophysics and long minutes would pa.s.s before Rick or Scotty could bring them back to the main point with a question.

In the midst of an interesting discussion of the Hawaiian volcanoes by Dr. Balgos, Honorario burst into the dining room and hurried to the Peruvian scientist. Rick couldn't follow the rapid Spanish, but Balgos jumped to his feet, his face white, and translated swiftly.

"Honorario says all the dynamite is gone!"

CHAPTER VI

Dangerous Trail

The search for the missing dynamite had failed completely. Rick, Scotty, and the scientists were equally puzzled. Why steal dynamite? What was there to be gained?

At a conference early the following morning Hartson Brant voiced the question.

Julius Weiss was the first to respond, and his answer was another question. "What was to be gained by stealing the tracings and Jeff's sketch? Isn't the theft of the dynamite in the same category?"

"I suppose it is," Hartson Brant agreed. "I see no motive whatever for either theft. After all, it was simple enough to make additional tracings, and it will not be difficult to obtain more dynamite. So I go back to my original question. What is to be gained by the theft?"

"Dynamite has some value," Zircon boomed.

"To be sure. But the tracings had none, except to us."

Rick said what had been on his mind. "Both thefts resulted in only one thing . . . delay. The tracings put us a day behind, and the dynamite might delay us even longer. It depends on how fast we can get more."

"Maybe Rick has something there," David Riddle said. "But who gains from a delay in the project?"

"No one," Brad Connel said testily. "I think we're looking for a motive that doesn't exist. The tracings probably were stolen by someone on the hotel staff, because they looked important. Maybe the thief thought they could be sold. Certainly the dynamite can be sold. What motive do we need other than the usual profit a thief expects?"

"Perhaps none," Hartson Brant admitted. "The question is, what now? We can proceed no further without explosives."

"I will go to the governor and see if he can obtain more for us,"

Esteben Balgos announced. "If he has none here on San Luz, there are other islands close by. A few telephone calls will locate a supply."

"Fine. And while you're doing that, there is little the rest of us can do except relax. Will you let us know by telephone what the governor says?"

"Yes, at once. Any of you care to go with me?"

Williams and Riddle volunteered to go along. Weiss announced that he wanted to make some calculations and asked Hartson Brant and Zircon to help him.

Rick and Scotty, left on their own, considered the possibilities for amus.e.m.e.nt and found none except the ocean itself--which was plenty.

They decided on a swim and hurried back to their room to put on trunks under their slacks. Zircon readily gave permission to use the jeep.

As they changed clothes, a jeep motor roared into life. Scotty walked to the window and opened the draperies. "Balgos and the others," he announced.

A few minutes later another jeep motor started up. Rick went to the window and was just in time to see Brad Connel start across the parking lot in his jeep. He was alone.

The boy turned away from the window, very thoughtful. "That was Connel.

Wonder where he's going?"

"Maybe to Calor, for shopping or sightseeing," Scotty replied. "What's on your mind?"

"He worries me," Rick said bluntly. "I don't really know why. Only he's certainly determined to keep us away from his firing stations, isn't he?"

"Go on. Something's biting you, and I want to know what it is."

Rick stared at his dark-haired pal without really seeing him. He struggled to put into words the vague thoughts in the back of his mind.

"Well, he acted worried about Ruiz, but I don't really think he was. It was kind of overdone, you know? His face didn't match his words."