"Since that is all settled," Mr. Brewster said, "suppose we go and talk to Dr. La Vega, over at the excavation. First, let's find out if Professor Bortha can come along."

"I don't think he can," said Biff, "because he has to 58 .

dictate his report on those inscriptions out at the pyramids. He said it would take him a couple of hours. But I'll go and ask him if he wants to come."

Inside the hotel was a patio, with rooms all along the far side, much like a modern hotel, though the hacienda had been built at the beginning of the century. Ted and Monica were at a table in a shady corner, playing a word game on a board that they had brought with them.

When Biff asked, "Have you seen Professor Bortha?" Ted nodded.

"He went into his room to work five minutes ago," said Ted, "and he's been at it ever since. Listen."

Biff listened. The precise tones of Professor Bortha were coming in sonorous style from a door that bore the number eight. Some of his words were in Spanish, but mostly he was quoting long sentences in a strange language which Biff decided must be Nahuatl, the native tongue of the Aztecs, though it could be mixed with Mayan, as spoken by the Toltecs.

As soon as Bortha paused, Biff knocked on the door, but the professor simply resumed his dictation. At another pause, Biff rapped again, this rime more loudly than politely. Professor Bortha opened the door, and said, "Oh, h.e.l.lo!" and then stepped back to turn off a tape recorder that was on his table.

When Biff asked whether he wanted to go with them to the excavation, the professor shook his head.

FOUR SLIPS OF PAPER 59.

"I've just started dictating the first reel," he said. "It will take a full hour, and then I'll begin the next one. I think two reels will just about do it. So tell Dr. La Vega that I'll see him in about two hours from now-or a little later."

Biff left, and Professor Bortha promptly resumed his tape recording, his voice coming through the closed door before Biff was halfway across the patio. Outside, Biff rejoined his father and Mike. He told them what Bortha had said, and they started on their way.

The path forked soon after it left the hotel. One branch turned steeply up the slope to join the pack trail which crossed the ridge just short of the towering cliff. The other branch descended gradually in back of the village until it reached the excavation cabin, below the cliff itself.

This was the path that Mr. Brewster and the boys followed. A ten-minute hike brought them to the cabin, and during the last stages, the cliff seemed to tower more and more formidably, until it finally seemed to be hanging directly above them. The cabin, built on rough, uneven stone, was like a toy in the grip of a monster's claws.

"Weird, isn't it?" Biff said to Mike, as they started up the cabin steps.

"I'll say," was Mike's reply. "It gives me the creeps to go inside the place!"

They didn't have to go inside, just then. Dr. La 60 .

Vega met them on the threshold, greeted Mr. Brewster with the warmth of an old friend, and shook hands cordially with the boys. Then he said: "Let us look at the excavation first, Senor Brewster. Then we can discuss our problems in a much clearer way."

The excavation began as a simple mine shaft, then leveled into a long tunnel lighted by a string of electric bulbs. Mr. Brewster examined the rough-hewn walls as they moved along.

"Undoubtedly of Aztec origin," he declared. "This tunnel was chopped out with very primitive tools."

They reached a chamber with a slanted ceiling formed by stones that appeared to be wedged in place. As Dr. La Vega pointed up into the light, his face resembled yellow parchment, smooth except for the few slight wrinkles of his constant smile.

"What about this?" he asked.

"Definitely not a mine," declared Mr. Brewster. "It looks more like an outer room of an old temple."

"Exactly," agreed Dr. La Vega. "It was filled with loose stones when we found it. We tapped the walls for other pa.s.sages and finally found this one."

He was leading the way to the far wall, and they climbed up through a slanted shaft to another chamber where the ceiling was sh.o.r.ed up with timbers. Here, half a dozen workers were digging into a pile of earth and stone that they had very nearly cleared.

FOUR SLIPS OF PAPER 61.

"Each time we dig out this room," stated Dr. La Vega, "there is another fall of stone. The natives are superst.i.tious"-he lowered his voice to an undertone -"so they blame it on Tizoc. The last time they cleared it, they thought they saw some of his Eagle Knights down here. It took me a week to get them back to work. By then, the room was filled again."

They went out through the tunnels, and Mr. Brewster made a new study of the walls as well as the supporting timbers.

"Those props look strong," he said, "but you can't be sure of anything while that stone keeps falling. This whole slope may be honeycombed with underground rooms and pa.s.sages, which makes it all the more dangerous. A big slide might take the shorings along with it.

"One thing is certain." They had reached the outer shaft when Mr. Brewster gave this final opinion. "This was not an ancient mine. There are no traces of any valuable ore. The Aztecs may have looked for gold here, but they did not find it."

Outside the shaft, the daylight seemed very bright indeed, despite the gloom cast by the overhanging cliff. As they followed Dr. La Vega into the cabin, Mike whispered to Biff.

"This doesn't bother me the least bit, now. That big cliff is nothing, after that trip underground. I don't blame the workers for wanting to get out."

62 .

The cabin was furnished much like an office, except for small living quarters in a back room and a kitchen galley adjoining it. Dr. La Vega offered coffee to his visitors and took his place behind a plain, flat desk, where he spread out a large chart and showed it to Mr. Brewster.

"Here is the work done so far," La Vega declared. "Now, instead of tunneling deeper, I am more inclined to excavate, digging away the entire surface, uncovering everything in order."

"That might be best," agreed Mr. Brewster, "now that you know that those are not mining tunnels."

"But the natives keep speaking of it as a mine," said Dr. La Vega. "They have kept that tradition from the early Spanish days, although the Spaniards never tried to work the mine."

"Naturally not," said Mr. Brewster. "One look would have convinced them that there was no gold there."

"And that may have been what the Aztecs wanted them to think. Because they were hiding something greater! Perhaps their own lost treasure!"

Dr. La Vega leaned across the desk, his eyes agleam with unrestrained excitement. Then, calming himself, he added: "There is a secret here somewhere, and someone is after that secret. This talk of Tizoc and the Eagle Knights is part of the game. I can prove it!"

FOUR SLIPS OF PAPER.

63.

He paused, glanced at his watch, and asked: "How soon did Professor Bortha say that he would be here?"

"In about two hours," replied Mr. Brewster, "from the time we left the hotel." He studied his own watch methodically. "That was almost an hour and a half ago."

"No need to wait, then," decided Dr. La Vega. "I wanted to show this to Bortha, too, but I can tell him about it later. Yesterday, some stranger handed one of our workers a message. He read it, tore it up, and threw away the pieces."

Dr. La Vega brought an envelope from the desk drawer, opened it, and slid some torn bits of paper onto the desk.

"Here are those pieces," he continued. "A loyal worker named Chaco gathered them and gave them to me. Look at these four first."

He laid the slips on the desk.

HOMBRE QUE ORO ROJO.

PLATA.

Mr. Brewster studied the slips and translated them: "Hombre-man. Que plata-What silver. Oro- gold. Rojo-red."

64 .

"And now," said Dr. La Vega, with a smile, "suppose we piece them with the other five and see what a difference-"

He halted and gave a sudden quiver. Biff stared, puzzled, for oddly, he felt himself shuddering, too. He looked at his father and at Mike. They also were shaking. Biff suddenly realized what was happening, even before Dr. La Vega exclaimed: "Outside-everyone-before we are swept away! This must be an earthquake!"

CHAPTER VIII.

Strange Disaster THE cabin itself was rocking by the time they reached the door. Its walls were cracking, buckling, and the ground, too, was sliding crazily as Biff and Mike landed there, with a side-by-side jump.

They came to their feet, hoping to help Mr. Brew-ster and Dr. La Vega, who by then should have been coming down the cabin steps. Instead, they saw Biff's father turning back into the cabin. Seconds later, he was coming out again, dragging Dr. La Vega with him.

They reached the steps, and there the old archeol-ogist broke away again, shouting that he had to save his records. Before Mr. Brewster could grab him, the cabin took a sidewise topple. Mr. Brewster landed beside the boys, while Dr. La Vega was carried along with the cabin, which looked as though it would go

65.

66 .

over the mountainside. But when Biff looked for the cabin, he saw it disappearing into the ground itself. Meanwhile, men were pouring out from the nearby shaft; they were the workers who had been below. Yet beyond them, the village of El Cielo stood undisturbed.

Biff turned to Mike, who was half sprawled on the ground and exclaimed: "This isn't an earthquake! It's a cave-in! The props have gone out from under!"

Biff had heard enough from his father regarding mine disasters to realize what had occurred. In those few moments, Mr. Brewster had already sized up the situation and was clambering forward, knee deep in cracking stone and sinking earth, to rescue Dr. La Vega, who was sliding down into the hole that had swallowed the cabin.

Both figures faded momentarily in a cloud of rising dust as Biff gripped Mike's arm and urged: "Come on! We've got to help them, or they'll never come out alive!"

It was a question, too, whether the boys would come out alive when they reached the spot where Mr. Brewster was dragging Dr. La Vega from the broken boards that had been the cabin steps. But the ground itself was spreading into the form of a huge funnel, making it impossible to climb up over the expanding rim.

68 .

Apparently, Dr. La Vega had been knocked unconscious by a falling chunk of wood or stone, for he was an inert figure in Mr. Brewster's grasp. Biff and Mike, tugging at Mr. Brewster's shoulders, kept slipping back at every try.

The scene resembled a volcanic crater, the thick, dry dust rising like a cloud of smoke. From its midst, Mr. Brewster spoke chokingly: "Get clear, boys! I'll try to hang on while you bring help. But get yourselves clear first!"

"We can't," panted Biff. "The whole ground is slipping in on us."

"If we don't get help now," added Mike fervently, "we never will!"

With that, help came. Down through the choking dust came a tawny face, below it, a white-shirted arm, with a brownish, brawny hand, that reached for Biff's. From the face above came the spoken order: "Grab quick! Chaco pull you out!"

Biff made a frantic upward scramble and caught Chaco's hand just in time to avoid slipping back. With his free hand, Biff caught one of Mike's. In turn, Mike was able to grip hands with Mr. Brewster, whose other arm was around Dr. La Vega's body.

Still, they were a long way from rescue; in fact, it seemed hopeless. Biff's arm seemed to be wrenched from its socket; he realized he could not stand the prolonged strain of all that weight. He wondered STRANGE DISASTER 69.

what would happen when Chaco began to pull on him.

But Chaco did not pull. Patiently, he waited, keeping his face lowered to avoid the dust, while Mr. Brewster worked one hand upward, using first Mike's body, then Biff's, as a human ladder, until finally he gripped Chaco's chunky form.

During that climb, most of the strain was on Mr. Brewster, who was dragging Dr. La Vega up with him. Biff and Mike simply hung on tight and dug into the slipping earth as well as they could. Then, when Mr. Brewster had gone out of sight into the dust beyond, Chaco told the boys: "Now, you come."

Now, for the first time, Chaco pulled, slowly, easily. With only Mike's weight hooked to his own, Biff did not feel too much strain. Biff clutched Chaco's body and continued on; a moment later, Mike did the same. Past Chaco, they found a human chain composed of the workers from the shaft, continuing on, six men in all, until it came to solid ground. There, another pair were acting as anchor men.

The going was easy during the final stages as the slant of the ground was less and the sliding earth comparatively slight. There was no more dust when they reached the solid ground and there, the boys found Mr. Brewster bending over Dr. La Vega, who was still unconscious.

Now the workers themselves came crawling up 70 .

from the funnel, human ladder style and Chaco, after a glance at Dr. La Vega, turned solemnly, inquiringly to Mr. Brewster.

"I think he will be all right," said Mr. Brewster, referring to Dr. La Vega. "But we must get him up to the hotel right away."

Chaco had two workers bring a stretcher from an emergency shack near the open shaft. They placed Dr. La Vega on it, and the two men carried the unconscious archeologist up the sloping path, with Mr. Brewster and Chaco walking alongside, keeping careful watch.

Mr. Brewster was limping slightly, at moments painfully; but neither Biff nor Mike had suffered more than a few minor bruises. Noting that the boys were in good shape and eager to help, Mr. Brewster suggested that they hurry ahead and arrange for the hotel to summon a physician.

The disaster at the foot of the cliff had been so sudden and so brief that it had failed to wake the sleepy village of El Cielo from its afternoon siesta. The news had not yet reached the hotel. But Mrs. Brewster, who was dozing in a chair while the twins still played their word game, woke instantly when the boys dashed into the patio. Sensing something wrong, she asked: "What has happened?"

"Dad is all right," Biff was quick to inform her, "but Dr. La Vega has been hurt in a cave-in."

STRANGE DISASTER 71.

"You had better tell Professor Bortha," said Mrs. Brewster. "He is still in his room, dictating his notes."

"Dad said to get a doctor."

"I'll have the hotel clerk send for one."

Bortha's loud, steady tone was still coming from room eight when Biff knocked on the door. This time, Bortha's dictation stopped suddenly, and he came to the door, holding the last page of his notes in one hand.