32 .

"During various excavations," Judge Arista went on, "Dr. La Vega has uncovered the shafts of several ancient mines. It is difficult to tell whether or not these date back before the Spanish Conquest. If they do, they are important, because in that case they were dug by the Aztecs themselves and may have been used as hiding places for their treasures.

"To determine this, we called upon a mining expert, Senor Thomas Brewster, who has come to Mexico to examine the excavations and give an opinion. If he finds that these are actually Aztec mines, more money will be raised to continue our work."

Judge Arista paused again and this time turned to Mr. Brewster with the query: "Have you any report to add, Senor Brewster?"

"Yes," replied Mr. Brewster. "From specimens of rock and fragments of timbers taken from the El Cielo excavation, I would say definitely that crude Aztec tools had been used in digging the old mine shafts. A full inspection is therefore advisable."

Ramonez took that down, too, then read it back in his smooth, precise tone. Biff's interest was now at a high pitch, for he had learned the part his father was to play, and it promised new adventure.

"Put this in the report," Judge Arista told Ramonez grimly. "Tonight, the entire Tizoc exhibit, the most valuable in our collection, was stolen from the museum rooms. Measures will be taken to prevent fur- THE MESSAGE OF MICTLAN 33.

ther thefts, but until those items are recovered, we are at a standstill. At least, we must learn the purpose behind this unforeseen outrage."

A voice spoke coolly, steadily, from the doorway: "I think I can answer that, Judge Arista."

Everyone turned to see a stockily built man with broad, blunt face and short-clipped hair, its reddish shade extremely light in contrast to his deeply tanned features. The lips above his wide jaw were set in a firm, serious line.

"Ah, Professor Bortha!" exclaimed Judge Arista. "I am glad you have arrived. You have heard what happened here?"

"I heard it just now," returned Professor Bortha, "but it does not surprise me. In El Cielo, our work has been interrupted by rumors that Tizoc, the War G.o.d, is planning to return. Workers claim that they have seen some of the Eagle Knights who once accompanied Tizoc as an honor guard.

"Rather than have such rumors grow, Dr. La Vega has halted work until we can make a thorough survey of the shafts so far uncovered and learn just where they lead. He wanted me to report all this, so two days ago, I started by pack mule over the high pa.s.ses of the Sierras and reached the railway this morning. There I took the train that brought me into Mexico City this evening."

Mr. Brewster had a query: 34 .

"Then it will take us three days to get to El Cielo?"

"Yes and no," replied Bortha. "We must wait three days, yes; but then with the right type of plane we can make the trip and land there in a mere hour or so. Dr. La Vega has put the entire excavation crew to work on the partly finished air strip, and it will be ready by the end of the week. From then on, El Cielo will be accessible at last."

Judge Arista had one final question: "Tell us, professor, have you any idea who might be behind this Tizoc rumor?"

"I thought it might be some local mining interest," replied Bortha. "That is why I tried to contact Mr. Brewster as soon as I arrived. I felt he was the man most qualified to give me an opinion. But now, with the Tizoc exhibit stolen, I am afraid that much bigger problems are involved. How big, I cannot say." He finished with a shrug: "I am an archeologist, not a detective."

Judge Arista added the statements of witnesses to the report and then closed the conference. Biff said good night to Mike and joined his father and Professor Bortha, who had decided to accompany the Brew-sters to their hotel. They rode in a car driven by Judge Arista's chauffeur and on the way, Biff asked in a puzzled tone: "How is it that we aren't pa.s.sing the Buenavista Station?"

"Why should we?" queried Professor Bortha. "It is THE MESSAGE OF MICTLAN 35.

way off in another direction. That is why I called your hotel before going to Judge Arista's."

"But the cab from the hotel brought me past the station."

"It did?" Bortha's wide forehead furrowed into sharp creases, straight like his lips. "And it was after that, you noticed that your cab was being followed?"

"Yes."

"Then whoever followed it must have been waiting outside the station, watching for me!"

Triumphantly, Bortha turned to Mr. Brewster.

"See how neatly it fits?" the professor queried. "Someone posted that cab outside the Hotel Del Monte to pick up your son or anyone else in the family who might be starting to meet you. So it swung by the station, gave a signal, and another cab picked up the trail."

"With the man who was watching for you?"

"Exactly," returned Bortha. "He may have known that we planned to meet. Therefore he would have considered one trail as good as the other."

"Do you think he was the man who stole the Tizoc costume?"

"I would say so, Mr. Brewster."

"And I," returned Mr. Brewster, "would say that for an archeologist, you are a good detective, Professor Bortha."

For the first time, Bortha's serious lips relaxed into a broad smile.

36 .

"I suppose the two have much in common," he said. "But a man should not wander far from his own field. I must confine my detective work to deciphering ancient inscriptions and identifying odd objects from the past."

"We'll give you a chance at that right now."

The cab was stopping at the Hotel Del Monte as Mr. Brewster spoke. Biff noticed a puzzled frown on Bortha's face as Mr. Brewster led the way upstairs.

Biff's father introduced Professor Bortha to Mrs. Brewster, then went directly to the table and picked up the miniature skull that was lying there.

"What do you make of this, professor?" he asked.

Bortha's eyes showed intense interest in the crystal skull.

"An authentic Aztec carving," he declared. "But how did it come here?"

Mr. Brewster nodded to Biff, who said: "I found it when I answered the telephone this evening."

"Before the call you mentioned at Judge Arista's home? When a voice said, 'Tizoc-Death-Beware!'?"

"Yes, sir."

"Then the threat was real indeed," Bortha's voice was low and impressive. "This is exactly what Tizoc himself would leave as a calling card." He held it so the crystal eyes glittered in the light. "This skull represents Mictlan, the Aztec G.o.d of Death!"

CHAPTER V.

The Clue of the Cab THE next morning, Biff arranged to meet Mike at the National Museum, hoping that they might uncover some chance clue to the Tizoc riddle, which still remained unsolved.

The museum, which had served as a government mint back in Spanish Colonial days, was located in back of the National Palace, and now its treasures were measured in terms of more than money.

Biff was greatly impressed by the huge Aztec Calendar Stone, which stood in the Gran Sala Mexica, a princ.i.p.al exhibit room. The stone measured twelve feet in diameter and weighed more than twenty tons. It had elaborate carvings representing the days of the Aztec month, and in the center was a face that Mike identified as Tonatiuh, the Aztec Sun G.o.d.

37.

38 .

Mike's ability to reel off those curious names and cla.s.sify them struck Biff as remarkable indeed.

"How you even remember them is one thing," declared Biff, "but keeping them straight would seem impossible-even for the Aztecs."

"In a way it was," Mike rejoined with a smile. "Some of them had special t.i.tles. Huitzilopochtli, for instance, was also known as Mexitli, from which the name Mexico comes. But Professor Bortha is the man to answer such questions."

Since Professor Bortha wasn't with them, Mike had to cover a few more details on his own. He showed Biff a sculptured head of an Eagle Knight, wearing a helmet shaped like the open beak of a bird. The sculpture represented one of the ancient warriors that Professor Bortha said the natives in El Cielo reportedly had seen.

There were carvings showing the conquests of Ti-zoc, in his garb as War G.o.d, with captives being brought before him. Other captives were depicted defending themselves against Eagle Knights, like ancient gladiators. But from these, neither Mike nor Biff could gain any explanation for the apparent return of Tizoc, the night before.

That was discussed later, when the judge's car stopped by and took them to the Arista home for an elaborate dinner that lasted from two o'clock until half past three. Biff's father was there, with Professor Bortha, and Ramonez was also present.

THE CLUE OF THE CAB 39.

Judge Arista looked from one to another, as he stated in a troubled tone: "If only one of you had been here at the time the boys went into the museum rooms!" He turned to Biff's father: "Unfortunately, Senor Brewster, you were still on your way here from the airport." He turned and bowed slightly to Bortha. "And you, professor, had not even arrived at Buenavista. As for Ramonez"-he gestured to the secretary, who was seated near him-"he had gone out. Unfortunately, neither the boys nor Hernandez had a chance to see the face of the man who stole the Tizoc mask and used it to hide his ident.i.ty."

"Perhaps we can trace his earlier actions," suggested Mr. Brewster. "The skull that was left at my hotel may be an important clue."

"I agree with that," put in Bortha, "and I can tell you this: If we fail to find this false Tizoc now, we shall have more trouble from him in the future."

"You mean in El Cielo?" Judge Arista asked.

"Very possibly," replied Bortha. "Tomorrow, I am going to San Juan Teotihuacan to examine some inscriptions that have been found in the archeological zone there. From the past we may gain knowledge of the future, where Mexican legends are concerned."

Biff, by now, had learned enough about the Aztecs to know that the arrival of the Spaniards under Cor-tez, in the year 1519, had been regarded by the natives as the fulfillment of an old prediction that a hero 40 .

G.o.d would someday come from the "Land of Sunrise" on a winged ship. From what Professor Bortha had just said, the return of Tizoc might be a modern myth of somewhat the same order.

There was another matter, however, that interested Biff still more. When he was alone with Mike, Biff asked: "Where was Ramonez yesterday afternoon?"

"I don't know," replied Mike. "He has a way of moving in and out like a cat."

"And what time did he go out later?"

"Soon after he telephoned your hotel to tell you to meet your father here."

As Biff pondered, Mike smiled.

"I know what you're thinking," said Mike. "Ramonez could have placed that crystal skull in your hotel room. He might have been the man who stole the Tizoc costume, too. Ramonez is a strange bird. My uncle has often said so."

"Then why does he keep Ramonez as a secretary?"

"Because the historical committee recommended him. He knows every detail about the collection in my uncle's museum. But Ramonez will be taking a vacation beginning tomorrow, because my uncle has decided to lock the museum rooms until the Tizoc mystery is solved."

When Biff and Mr. Brewster were riding back to the hotel, Biff mentioned his suspicions of Ramonez.

THE CLUE OF THE CAB 41.

"Suspicion is one thing," Biff's father declared. "Proof is another. Let's not be too sure about Ramonez -one way or the other."

At the hotel, Biff and his father were met by a quiet man who introduced himself as Inspector Gonzales of the Mexico City police. He stated that he had questioned persons working at the hotel and had learned that a maid had left the Brewster suite unlocked the previous afternoon.

"Someone probably sneaked in and left the crystal skull," the inspector stated, "but no suspicious characters were noticed. That leaves us only one lead." He turned to Biff. "What about the cab driver who picked you up outside the hotel?"

"He drove up as soon as I came out," replied Biff, "and he pointed to a sign that said 'Libre,' but I didn't notice him closely. I was busy telling him where I wanted to go."

"And did he try to make a price? Or did he charge you according to the meter."

"According to the meter."

Inspector Gonzales gave a tired smile.

"All day," he said, "we have been talking to drivers of turismo cabs who stay outside hotels and make special prices for tourists. But this must have been a cruising cab, or a sitio cab from a regular cab stand. How well did the driver speak English?"

"Not too well," returned Biff. "I talked to him in 42 .

Spanish. He kept saying, lToto va biert and finally he said, 'Estamos' and waited for me to pay him off, which I did."

Inspector Gonzales kept making notes of all that Biff told him. While this was going on, Mrs. Brewster came into the lobby with the twins, Ted and Monica. They had been sightseeing all day, and this was the first time that the twins realized that some mystery was afoot. Quietly, Biff's father explained to them that Inspector Gonzales was checking on suspicious persons who had been around the hotel the day before.

"Somebody must have paid that driver to wait outside this hotel," Inspector Gonzales was telling Biff. "Just to pick you up when you came out. I'd like to know what he looked like!"

Monica stepped forward.

"He was a big man," she said. "He was an American, and he was wearing gray trousers and a tight-fitting sport jacket. I didn't see his face, because he had a big ranchero hat, and he kept his head tilted like this"-Monica dropped her head to the left-"while he talked to the cab driver."

Inspector Gonzales listened with mingled surprise and admiration. Then he said: "Repeat that again, please."

Monica repeated it, word for word, and the inspector jotted it down and then asked: "What else did you notice about him?"

THE CLUE OF THE CAB 43.

"He had a big, round face," recalled Monica. "Like a moon face. A reddish face, too. I noticed that because the cab driver's face was much darker. Anyway, the man with the big hat was pointing us out to the driver. When he saw me looking at them, he turned and walked away, and the cab driver went back to his cab."

"When did this happen?" put in Ted. "Or are you just making it up?"