Rick shrugged. "How can we know that? For all we know, from his third shot station he might be able to look right down on the trail. He sees us, hurries into position, fires the charge, and hurries back. We can"t really tell until we get to that third station. Personally, I vote for Connel."
"Not proven," Scotty warned.
Rick knew it. "It may never be proven, on account of no witnesses. But suppose it was some unknown party? Why wouldn"t that party try for Connel? Why wait until he"s pa.s.sed, and we"re coming into position? Would an unknown thief be that interested in us?"
"Too many questions," Scotty objected. "I haven"t any answers. But you make a good case for its being Connel. Also, did you notice how he jumped on us for stealing the dynamite? That probably would have been his story if we"d been killed. Now tell me what his motive is. Why should he try to delay the project?"
Rick had no answer to that. "Makes no sense," he agreed. "Unless there"s something he doesn"t want us to see. That dynamite sure discouraged our trip to his third station!"
CHAPTER VII.
CASA GUEVARA.
THE scientific party lost only one day because of the dynamite theft. Governor Montoya supplied more explosives and the firing schedule continued. Now, however, the dynamite was guarded by police supplied by His Excellency. Police also were in evidence around the Hot Springs Hotel. No more chances were being taken.
After three days, the scientists began to have a better idea of what was going on in the earth beneath them, but Rick and Scotty could make little sense of the ma.s.s of data. Even the picture being filled in by Dr. Williams was confusing. Now, two magma areas were showing where only one had shown before.
Esteben Balgos answered Rick"s plea for an explanation. Over an excellent dinner of roast suckling pig and bananas steamed with lemon juice, the volcanologist took time to answer their questions.
"There is much we do not know about volcanoes," the Peruvian scientist began. "For example, we do not know exactly what causes magma to form. Magma is, in simplest terms, molten rock. Some event takes place far below, where the earth"s crust ends and the mantle begins, and the rock melts."
"How far below?" Rick asked.
"The distance varies. Under the ocean trenches, for example, the mantle may begin only four miles down. Under some of the mountainous land ma.s.ses it may be closer to forty miles."
Scotty whistled. "That"s a whale of a distance. How can you tell how far down it is?"
"By the seismic traces from earthquakes, or from explosive shots like the ones we are shooting. When the shock waves have reached the zone between the earth"s crust and the mantle, we see the results on our tracings."
"Is it really a sharp line?" Rick queried.
"Probably not. No one is sure yet. It may be a kind of transitional zone, from one kind of material to another, or it may be a distinct layer. We call it the Mohorovicic Discontinuity, after the Yugoslav scientist who discovered it by a.n.a.lysis of seismic tracings. At any rate, it is somewhat above this discontinuity that magma is formed. We don"t know how."
"Then it rises?" Scotty asked.
"It forces its way up, by expansion. Sometimes the magma strikes water and there is an explosion-a steam explosion. But generally the magma rises through a fairly small channel. It forms a pool under the volcano. The pool is actually a reservoir of molten rock. Generally it is shaped like a lens. The magma gathers. Eventually it forces its way to the surface, again through channels."
"What kind of channels?" Rick asked.
"It depends on the kind of volcano. Sometimes the channels are weaknesses in the whole surrounding earth structure, and the magma flows through cracks and emerges as sheets of lava. Sometimes there is a central channel through which the magma can rise."
"Which do we have?" Scotty wanted to know.
"Probably neither or perhaps both. There was once a central channel in El Viejo. It is closed now, and we do not know if it is weaker than the rest of the mountain. There is a weak fissure under the hot springs. So, El Viejo can vent either way."
Rick shook his head. He had learned enough of natural forces to know there are often no definite answers to questions, but this was critical.
"So the volcano could blow off on top or side, and we can"t guess which?"
"That is correct. However, explosive action in a volcano usually comes when the magma meets enough water to create steam. Now, our closest magma front is still far below the floor of the surrounding ocean. You follow me? Good. When the magma rises to the level of the ocean floor, what do you think will happen?"
Rick could see the picture in his mind. He said slowly, "It will probably meet water. Plenty of it, from seepage of the ocean downward through cracks in the ocean floor. Maybe there are cracks like the one in the parking lot, caused by earthquakes."
"Precisely. And when the magma meets the water, then what?"
"The water turns to steam instantly." Scotty answered grimly. "The steam expands instantly-and boom!"
"Boom," Balgos agreed solemnly. "But how big a boom we do not know. It may blow the top off El Viejo. It may blow a gap along one of the cracks. We don"t know."
Rick digested this information in silence. The picture was certainly not a cheerful one. "How far down are the magma fronts?" he asked.
"As closely as we can tell, the bottom one is right above the discontinuity, which is about six miles below us at this point. The upper one is about a mile below the top of El Viejo. This puts it about a quarter of a mile below the floor of the ocean."
"Too close," Scotty muttered. "What now?"
"We keep shooting, to try and keep track of the upper front. Also, we will place instruments called tiltometers on the mountain slope. These are devices that really measure tilt. You see, if the lens of magma is increasing, El Viejo will swell up slightly. The tiltometers will show it, and we will then have further proof of what is coming."
"But what can we do about it?" Rick demanded.
Balgos shrugged. "Quien sabe? The Spanish phrase is a good one, because it does not only ask "who knows," it also carries the meaning of a kind of resignation. There does not seem to be anything we can do."
Rick stared across the dining room, eyes unseeing. It was hard to imagine that molten rock was gathering below them in sufficient quant.i.ty to make a mountain move; but once you succeeded in imagining it, the picture was terrifying.
Motion attracted his glance and his eyes focused in time to see Brad Connel rise from the table and excuse himself. He watched the geologist walk out of the room and turned to Scotty. His pal nodded. He had seen Connel leave, too.
Rick quickly counted noses. All others were present. Connel was the first to leave. He wondered where the geologist was going, and his eyes narrowed.
Connel had been very anxious about his and Scotty"s condition, once the hotel was reached. Rick was sure his anxiety was strictly phony. Both boys had been stiff and sore, but a medical examination showed nothing seriously wrong, thanks to Scotty"s fast action. Hartson Brant had been reluctant to accept Rick"s opinion that Connel had stolen the dynamite and b.o.o.by-trapped them. He pointed out that the geologist had no motive; he had never even been on San Luz before.
Rick had to agree. There was no apparent motive, but that didn"t mean Connel was innocent. He might have a motive that no one suspected.
Scotty c.o.c.ked an eyebrow at Rick and made a slight motion of his head toward the door where Connel had vanished. Rick got the signal. He nodded.
The boys thanked Dr. Balgos for his explanation, then excused themselves. They wandered casually from the dining room.
Once outside, Rick grinned at Scotty. "So you"re wondering where Connel has gone?"
"Aren"t you?"
"Sure. But why not ask the others what he said when he excused himself?"
Scotty shook his head. "They didn"t think much of our theory about Connel causing our troubles, did they? If we asked, they"d think we were pushing the same point too hard."
Rick agreed. "Where did he go?"
"I don"t know. But if he leaves the hotel, it will be by jeep. There"s nothing within walking distance. If we get out back of the pump shed we"ll see him if he comes out."
"Aye, aye. And if he jeeps out of here, we"ll be on his tail. Roger?"
"You said a Brantish mouthful. Let"s go."
A quick reconnaissance disclosed no sign of the geologist outside, and the boys hurried across the dark parking lot to the shadow of the pump shed. A police officer materialized from the darkness and greeted them courteously. "Good evening, senores. A SMS ordenes."
By placing himself at their orders, the officer was politely asking their business, Rick knew. He replied, "We came out to see if anyone had made another try for the dynamite, Sefior Teniente." Calling the officer "lieutenant" was a form of flattery.
"Sargento, muchas gracias" the officer replied. White teeth flashed in a grin. "But who can tell the future? If I capture the thief, it may soon be lieutenant instead of sergeant."
"We hope so," Scotty said politely.
Rick noted that the three were hidden from the parking lot by the pump house. The position was satisfactory. If Connel was going to take a jeep, he probably would do so right away. Otherwise, why should he be the first to leave the dining room?
"Why would anyone steal dynamite?" Rick asked the police officer. He wanted only to keep a quiet conversation going behind the pump house.
The officer had theories. Perhaps revolutionaries had stolen it. Also, although it was against the law and brought severe punishment, fishermen were known to dynamite fish. This also was a possibility. But the explosion of the dynamite on the mountainside was certainly a puzzle.
Rick didn"t think so, but he agreed politely. It was bewildering, he said. Why steal explosives and then use it on a harmless scientific group?
Perhaps fear of discovery caused the thief to set a trap, the officer guessed. He admitted it wasn"t a good guess.
A jeep roared into life and the boys stiffened. The officer strolled out of the shadow for a look. "One of your a.s.sociates is going for a ride," he said.
Rick waited until the jeep lights cut across the parking lot and moved down the western road, then he said, "It"s a nice night for a ride, Scotty. What say we take a jeep and look over the country, too?"
"Good idea," Scotty agreed readily.
They bade the officer good night and started to where Zircon"s jeep was parked. It was a temptation to hurry, but they suppressed it and sauntered to the jeep. Fortunately, no keys were needed. The jeep ignition was turned on by a simple switch. Rick got into the driver"s seat and started up. He waited, the motor idling, until he was sure Connel was out of sight around the mountain, then he drove slowly across the parking lot and followed.
Fortunately, there was enough moonlight to see the road. Once out of sight of the hotel, Rick stopped and switched off the lights. As his eyes adjusted to the dimness he started off again as fast as vision allowed.
Once he sighted Connel"s lights. They were ahead and higher on the mountain. He lost sight of them again as foliage blocked the view. "Suppose he"s heading for the shot station?" he asked.
Scotty shrugged. "We"ll soon know."
They reached the pumice works without seeing the geologist"s lights again, and Rick stopped at the turn-off. "Now what?" he asked. "Did he go up the trail or not?"
Scotty sniffed the air. "Smell anything?"
Rick breathed deeply. There was the odor of rank vegetation, and, very faintly, the odor of sulfur from the hot springs. But there was another smell, too. After a moment he identified it. "Dust!"
"Seems so," Scotty agreed. "Which means he didn"t take the trail to the stations. No dust on those tracks. He must have taken the dirt road to San Souci."
"But why?" Rick was already moving ahead to where the pavement ended. "What"s in San Souci?"
Scotty chuckled. "Ask Connel. Don"t ask me."
"I thought Marines knew everything," Rick gibed.
"Almost everything," Scotty corrected.
The jeep moved onto the dirt road and in a moment their own cloud of dust obscured any slight haze that Connel"s pa.s.sing might have left. They were in strange territory now, and Rick slowed down somewhat. Connel had the advantage of lights. They wouldn"t be able to gain on him.
"He can"t get far," Scotty said rea.s.suringly. "The road goes to San Souci and nowhere else. It can"t be much of a town, so we"ll find him."
Scotty was right. San Souci wasn"t much of a town. There were a handful of fishermen"s huts, a dock with a number of fishing boats, racks for drying fish, a single store, and nothing else. There was a paved road leading from the town to the main city of Calor, but Connel hadn"t taken it. Nor was the jeep in San Souci.
Rick"s halting Spanish was sufficient to communicate with a fisherman who spoke equally halting English. He had been taking the air all evening. No other vehicle had come to San Souci.
"Now what?" Rick asked helplessly.
"He went somewhere," Scotty responded. "And that somewhere has to be a turnoff between here and the pumice works. We must have missed it because we traveled without lights. Let"s go back and look."
"I"m with you," Rick agreed. "But wherever he turned off must be a trail, because there are no side roads on the map." He swung the jeep around and started back. He had turned on the headlights as they approached the fishing village; he kept them on.
They found the turnoff about a mile from San Souci. The road widened slightly, and there was an opening in the foliage just wide enough for a car. Twin gateposts of concrete marked the pa.s.sage. Rick turned the jeep, and the headlights picked out a name cut in the concrete pillars: Casa Guevara.
"Someone"s house," Rick said. "Name of Guevara. We can"t very well go rolling up a private driveway, can we?"
"Especially with that sign," Scotty added. He pointed to a wooden sign set slightly to one side of the private road just beyond the gate. It read No Entrar. No Trespa.s.sing.
"Question," Rick said thoughtfully. "Did Connel go up this road or is there another one?"
"No evidence," Scotty replied.
Rick pointed to the gatepost. "Who do we know that"s named Guevara?"
Scotty breathed, "Sure! The lieutenant governor!"
"And he took Connel to the hospital to see Ruiz," Rick reminded, "so they"re acquainted."
He switched off the lights. "That"s probably the answer. Connel was invited to pay a social call. Why not? This probably has nothing to do with the project at all."
Scotty sighed audibly. "The trouble with you is that you come up with sensible answers. We might as well go on back to the hotel."
"Might as well..." Rick began, then stopped as light appeared dimly through the foliage up the private driveway. They were headlights!
"We"ve got to get out of here," he said, and threw the jeep into gear. For a moment he hesitated. If he went up the dirt road to the hotel, Connel would surely see them. If Rick went back toward San Souci and the oncoming car was not Connel, but someone from Casa Guevara, the car might also turn toward San Souci, and the boys would be seen.
Rick thought quickly. About a hundred yards toward San Souci there was a break in the foliage that he had almost investigated until he saw that no tracks led into it. He quickly switched into four-wheel drive and swung the jeep in its own length. The lights were closer now. Rick accelerated and found the opening through the jungle scrub. The jeep bounced as he drove into it, then swung until they were behind a screen of palmetto. He killed the engine.
Scotty piled out, Rick close behind him. They hurried to the edge of the highway, careful to keep masked by the palmetto, and watched.