The crack, however, went down only about three feet, gradually narrowing until it was closed. Even so, it was impressive. Rick knew that the actual break must continue down into the earth for some distance, perhaps for hundreds of feet. The force it took to shake the earth like that was awesome. Again he was reminded sharply of the kind of forces against which the Spindrift group was trying to contend, and he felt for the first time that the job was completely hopeless. What could mere men do?

A horn honking wildly brought him to quick attention. He turned and saw a jeep coming along the western road into the parking lot. Brad Connel!

But where was Ruiz? Then, as the jeep neared, Rick saw. The San Luzian was lashed to an improvised stretcher lying across the back of the jeep!

The geologist drew to a stop, his face chalky.

"Get a doctor!" he shouted. "Quickly! Ruiz got caught in the last explosion. I think he's dead!"

CHAPTER IV

Seismic Tracings

Ruiz, the short, friendly San Luzian, was not dead, but he was only barely alive. Within a half hour he was on his way to the hospital at Calor, crushed and unconscious.

Brad Connel was badly shaken. "I thought he was behind me," the geologist explained. "But he had gone back to check the cap connection.

At least, that's what he must have gone back for. I fired, then turned around, and he wasn't there. He was blown fifty feet at least. If only I had checked! But he was there with me, and I just kept my eye on the chronometer. He didn't say anything. He just walked off."

There was nothing much to be said. It was the kind of accident that seems absolutely senseless. Both Connel and Ruiz were old hands with explosives, yet the San Luzian apparently had wandered back to the charge just as it went off.

Rick and Scotty walked toward the hot springs behind the hotel and talked it over.

"Pretty stupid thing for anyone to do," Scotty said soberly.

Rick agreed. "Especially an old hand. Ruiz was supposed to be experienced, but I can't imagine how a veteran could pull a stunt like that."

It made absolutely no sense. Ruiz spoke English. Rick knew that from his conversation with the San Luzian. So he must have known Connel was counting down, getting ready to push the plunger home. Why would he walk into the blast, unless he was tired of living? But he didn't believe Ruiz would try to get himself killed deliberately. The little San Luzian had seemed like a sane, happy individual.

Rick gave up. Maybe when Connel calmed down a little he could shed more light on the accident. "The smell from the springs is getting pretty strong," Scotty remarked.

It certainly was. The wind had been from the hotel toward the hot springs most of the day, and the odor hadn't been bad. Now, in the vicinity of the springs, it was making Rick's eyes water and his nose smart.

"Think we can get close enough for a look?" Rick asked.

"We can try. There's the building ahead."

A cement walk led from the hotel to the springs, rising up a gradual incline that was not too steep for wheel chairs, or for the elderly. The boys had heard that many invalids had come here, to bathe in the hot springs, to drink the mineral water, and to soak in warm mud.

"How'd you like a nice hot mud bath?" Rick asked.

Scotty grinned. "Can't say it appeals to me, but there must be something to it. There are mud baths and hot springs in Europe, too. With plenty of customers."

Rick took out his handkerchief and dried eyes that were watering from the fumes. He doubted that the gases were good for them, but he was curious. He wanted to see where the volcano would blow its top, if it was going to.

In spite of the irritating fumes, they persisted and got a quick look at the former health area. There was a series of pools for bathers, ranging from big ones for large groups to individual tublike affairs, all nicely tiled. There was one area of mud baths. Rick had an impression of two areas, one of bubbling mud, the other of steaming water. It was enough.

The boys turned and got out of there.

Back at the hotel, the scientists were working. All were present, except for Brad Connel, who had asked to be excused. He was in his room, apparently still badly upset over the accident.

Dr. Jeffrey Williams had obtained a large sheet of paper and had sketched an outline of the volcano and the earth under it as seen in cross section. As Hartson Brant read off data from the day's tracings, Dr. Williams plotted points far underground. Now and then he connected points, or put in a light line.

Rick and Scotty watched with interest. The tracings meant nothing to them; a.n.a.lysis was a job for trained scientists. But Dr. Williams was slowly producing a picture on the paper.

"That's all," Hartson Brant said finally. "How does it look, Jeff?"

The seismologist shook his head. "Not good." He held his pencil almost flat to the paper and began shading in an area bounded by the points he had made. "According to what we have, this is the shape of a magma front." He drew in other lines, rising vertically through the earth into the volcano. "Apparently these discontinuities indicate old channels, now filled in. Notice that the magma is not following the original channels. This seems to confirm what Esteben has been telling us."

The volcanologist nodded. "It seems to. Jeff, do you have any doubt about this area being magma?"

"I'm afraid not. The data fits. Of course it's still pretty far below the surface."

Rick could see that the ominous shading was nearly twice as far underground as the top of the volcano was above sea level.

Julius Weiss spoke up. "The next step is to find out how fast the magma is rising."

"A series of shots every day for the next few days should tell us that,"

Hartson Brant agreed. "Hobart, you've been pretty quiet. Any comments?"

"None of any importance," the big physicist boomed. "Only this: what can we possibly do about a situation like this?"

Hartson Brant shrugged. "I don't know. At least we can keep track of the magma."

David Riddle, the geologist, added, "It will allow time to warn the population. I can see no other means of saving them except to get them off the island."

Rick had reached the same conclusion. It didn't take a scientist to realize the gravity of the situation. El Viejo was getting ready for something big, unless the magma subsided. Since no one was really sure about the physics of volcanology, no one had a good guess why the volcanic action had begun again. No one could be sure it would not decrease, either.

"This picture is pretty rough," Dr. Williams said. "I'll refine it a little after dinner, Hartson. It will give us a better basis for plotting tomorrow's results."

"Good idea," Hartson Brant agreed. "And speaking of dinner, it's about time. Let's wash up and meet in the dining room in a half hour."

"Better call Brad Connel," Zircon said. "I know how upset he must be, but it will be better if he joins us and eats something."

Rick and Scotty returned to their room and washed for dinner. Both were quiet. The appearance of the magma under them, almost like a mushroom cloud in shape, was pretty ominous. Like sitting on a volcano, Rick thought. It was the most appropriate expression he could think of. No wonder the earth had split.

Scotty mused aloud. "Rock. Melting like b.u.t.ter on a stove. Thousands of tons of it. Makes you appreciate natural forces, doesn't it?"

"Even hydrogen bombs are pretty feeble by comparison," Rick agreed. "It makes me uneasy to think of all that stuff boiling up under us."

"I caught myself looking down a couple of times," Scotty said with a grin. "I wouldn't be surprised to see steam coming up through the rug."

Rick consulted his watch. "Maybe food will make us feel better. Come on.

It's about time."

The scientific party was alone in the hotel, except for a reduced staff.

The governor had made arrangements for the hotel to operate so that the visitors could have service. Rick almost wished they had stayed at a beach hotel with other people around them. The huge resort was like an abandoned city, with a few ghosts left in it.