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."

Scotty shook his head. "You're on thin ice, boy. People don't react to accidents in a standard way. It might have been overdone, but it might not, too. What else?"

"He didn't want us to go along as helpers after Ruiz was hurt. I know that doesn't mean much, and he said he was just afraid of another accident, but wouldn't you think he'd like some company? Besides, two accidents like that just don't happen. Then, when we suggested changing stations so he could have more time to work on other things, he yelled pretty fast."

"Because we don't know his terrain," Scotty pointed out. "At least that's what he said."

"Sure. But what's to know about the terrain? All we'd have to do would be to follow his jeep tracks, and shoot where the ground is already torn up from his earlier shots. If it's safe for him to carry caps and dynamite, it's safe for us."

Scotty scratched his chin thoughtfully. "I see what you mean. But the evidence isn't very conclusive, is it?

"No," Rick admitted. "Only where's he going now? If he planned to go to town, he'd invite anyone who wanted to go, wouldn't he? That's what most people would do."

Scotty chuckled. "One thing I like about you. When you get a notion in that noggin, it doesn't come out easily. Next you'll be suggesting that he slugged Williams and stole the dynamite."

"He could have," Rick pointed out. "Apparently he was alone in his room both times. At least no one said he was with them."

Scotty held up his hands in surrender. "Okay. What do we do about it?"

"Let's see where he's going."

"I knew it," Scotty said resignedly. "Okay. But we'd better hurry."

There was a clear view from the front of the hotel down the slopes of the foothills to the town of Calor. The road wound around and occasionally vanished from sight in clumps of green growth, but the boys watched for several minutes and saw no sign of Connel. The jeep with Balgos and the others was rolling along in the distance, but it was still close enough to see three occupants.

"He didn't go to town," Rick said finally, "and there's only one other road out of here."

"To the shot stations," Scotty agreed. "Unless he cut off and headed for San Souci." That was a little fishing village on the west coast. Neither boy had been there, but they had used a flagpole on the .tip of the cape near the town as a sighting marker.

"Let's go see," Rick suggested.

They hurried through the hotel to the parking lot and got into the jeep. Rick started the vehicle, crossed the fissure in the lot, and took the road west. According to the map, the road was paved as far as the pumice works. Beyond that it was graded dirt. If Connel had taken the dirt road, instead of the trail to the shot stations, they should see dust.

He kept the jeep rolling at good speed as far as the pumice-works shacks, then stopped to look for signs of a dust haze. There was none. At the end of the blacktop, he and Scotty got out and examined the road surface. There were signs of traffic, but none very recent so far as they could tell. Rick drove the jeep a few hundred yards along the road, then got out and looked again. The heavy treads of his vehicle were clearly visible in the dust. If Connel had gone this way, he would have left similar marks.

"He took the trail," Rick said.

Scotty nodded. "Looks like it. Do we follow?"

"We sure do. What reason would he have for going to the station without dynamite?"

"None that I know of. Let's go."

Rick turned the jeep into the trail and sped along it as fast as the ruts allowed. As they reached their third station with no sign of Connel, Scotty spoke suddenly. "Suppose we find him? How do we explain why we're following him?"

Rick considered. He rejected a casual trip as explanation. Connel wouldn't buy it.

"We can park the jeep in the jungle," he said finally. "It will be well hidden. Then we can go on foot. If we see him coming, we can take to the bush. We'll be invisible a few feet away."

The jeep was driven into the area where their shots had been set off. It was invisible from the trail. The boys left it and started hiking.

It was hard going. The heat and humidity were both high, and they were sweating before a quarter mile was covered. The film of perspiration seemed to attract insects, too, and before long the pests were driving them to distraction. Rick brushed futilely at the shining swarm of gnats around his head. "I'm not sure it's worth it," he said grimly.

"Neither am I," Scotty agreed. "But we've started. Let's keep plugging."

They reached the first of Connel's shot stations without a sign of the geologist. It was much like their own, a small clearing with the ground torn by the dynamite.

The second station, a mile farther on, was similar except that there were more trees and fewer scrub palms. Rick identified one giant tree as mahogany.

They strode up the trail, grimly determined to find the geologist. One more station remained ahead. Rick doubted that he had gone farther than that. He wiped his streaming face and squinted his eyes to protect them from the whining gnats. They swarmed around but didn't seem to sting or bite. He was grateful for that much.

Suddenly Scotty let out a warning gasp. The dark-haired boy threw himself sideways, on top of Rick, and the two of them crashed to the ground.

"Roll away," Scotty said urgently. "Back! Hurry!"

The ground opened up a few feet away. Rick felt a giant hand pick him up, shake him, then slam him into a palmetto. Bruised and dazed, he grabbed the palmetto for support and lacerated his hands on the rough covering. He slid to the ground, consciousness slipping from him.

For a moment Rick lay slumped at the base of the palmetto. He didn't lose consciousness completely, but he was stunned and unable to function either mentally or physically. He had neither sight or hearing for the first few seconds, then these faculties slowly returned. He became aware that he was looking down at a broad green leaf, and that the leaf was gradually turning crimson.

He watched, his vision clearing, and suddenly realized that the red pigment was dripping onto the leaf in a steady series of drops that was almost a stream. At almost the same instant he knew that the red was blood and that it was his. He shook his head to clear it, and the red spray flew from side to side. Through the periphery of vision he saw that it was coming from his nose.

Rick realized that he was on his hands and knees. He rose to a kneeling position and fished for his handkerchief. He put it to his nose and it came away stained red. He sighed with relief. Nosebleed. For a moment he had wondered....

A few feet away Scotty was slowly stretching one limb after another, checking to be sure he was functioning. Satisfied, the ex-Marine sat up, with some effort. Rick saw that his nose was bleeding, too.

"You've got a nosebleed," Rick said faintly.

Scotty touched his nose with the back of his hand and examined the red trace. "Uhuh," he agreed.

"What happened?" Rick asked weakly. His voice sounded far away!

Scotty's answer was barely audible. "We found the missing dynamite. I saw a length of wire along the trail. Are you okay?"

"I think so." Rick got to his feet, feeling as though his body were in sections. "We must have been close when it went off."

The two held onto each other for mutual support while strength came back into them.

"We weren't too close," Scotty said finally. He gestured up the trail. Rick looked, and saw a gaping hole some distance away. Beyond it, coming toward them at as high a speed as the trail allowed, was Brad Connel in his jeep.

The geologist stopped as he reached the hole, then swung off the trail and plowed through some scrub and back onto it again. He drew up next to the boys.

"So it was you who stole the dynamite!" the geologist said grimly. "What happened? Did it explode while you were fooling around with it?"

The boys stared at him, dazed and openmouthed.

"You're crazy," Rick managed finally. "We didn't steal it, but we almost got blown up in it. If Scotty hadn't seen the wire, both would have been blown to bits."

The geologist's eyes narrowed. "Do you mean to tell me someone tried to blow you up? That's nonsense!"

"That's what happened, nonsense or not," Rick said curtly.

Scotty added, "And what were you doing here?"

"Came to get my wallet," the geologist answered readily. "I missed it and figured I must have dropped it up here. It wasn't anywhere else I'd been. Better get in and let me take you back. If you were close enough to get nosebleeds you must be shaken up quite a bit."

"We're shaken," Rick agreed. "Our jeep is down at our shot station. We decided to leave it there and take a hike."

They climbed into the back of Connel's jeep. The nosebleeds had stopped now, but their faces were smeared with blood. Neither felt like talking, nor, apparently, did Connel. He stopped at their third station and asked, "Can you make it? Or do you want to ride back with me?"

"We can make it," Rick said. "Thanks for the lift."

"I'd better stay behind you to make sure," Connel stated.

The boys headed straight back to the hotel, Connel a hundred yards to their rear. In the parking lot they thanked him again for the lift, then hurried in to let warm water wash away the traces of their experience.

Later, stretched out on their beds, they talked it over.

"You saved our bacon," Rick stated. "But what really happened?"

"I'm not sure," Scotty replied. "There are two possibilities. One, we sprung a b.o.o.by trap. I don't really credit that one much, because we were rolling away when the stuff let go. If we'd hit a trip wire or something similar, the dynamite would have gone off right then. So, second possibility, someone was waiting for us. We jumped back just as he pushed the plunger. Or, maybe he saw we had spotted the trap and tried to get us, anyway."

"Who's he?" Rick asked.

"Persons unknown," Scotty answered. "Or maybe one person not unknown."

"Meaning Connel? He could have done it. Suppose he set the trap, then took his jeep up the hill out of sight. Then he could have walked back, fired the shot, hurried back for his jeep, and driven down."

"Could be," Scotty agreed. "Only, did he know we were coming?"