"It was many years later that some one conceived the idea of building a temple around the air geyser to house the priesthood and holy of holies. Thousands of slaves were captured and set to cutting the lava blocks that were to form the temple walls. Innumerable water suits and helmets were made. The most difficult part of the work was the capping of the air geyser, but this was finally accomplished; then the building of the temple commenced. It took a thousand years and cost twice that many lives. When it was completed and tightly sealed, it was, of course, entirely filled with water; but when the valve that had been installed in the geyser cap was opened, the water was forced out of the temple through a one-way valve. Today, the geyser furnishes pure air for the temple and actuates the doors of the air chambers."
"How wonderful!" commented Helen. "But where does this air supply come from?"
"It is, of course, mere conjecture," replied Herkuf; "but the theory is that during a great eruption, when Tuen-Baka was an active volcano, the entire top of the mountain was blown off and that when a great portion of it fell back into the crater it imprisoned a vast quantity of air, under great pressure, in a subterranean reservoir."
"And when that supply is exhausted?" inquired the girl.
Herkuf shrugged. "Horus will reclaim the temple. But there is yet a second theory. It is possible that there exists beneath the temple an immense deposit of the very chemicals that we use in our helmets, and that the trickling of water from the lake into this deposit is constantly generating fresh air."
"What a world of thought and labor and lives must have gone into the building of that structure!" exclaimed Helen, "and to what purpose? Why do men so waste their energies?"
"Does your race build no temples to its gods?" asked Herkuf.
CHAPTER 27
Magra and Gregory halted on a rocky hillside above Ashair. The hot sun beat down upon them from a cloudless sky, the frowning walls of Tuen-Baka towered above them, below them stretched the calm waters of sacred Horas; and in the distance the entrance to the tunnel leading to the outer world beckoned to them and mocked them.
"Well, here we are," said Gregory. "This must be the secret entrance to the tunnel."
"Yes," said Magra, "we are here; but what now?"
"After what those poor devils told us," replied Gregory, "I think it would be foolish to throw our lives away uselessly by entering such a trap."
"I quite agree with you," said Magra. "We could accomplish nothing if we succeeded in getting into the temple. We'd only be captured and upset all of Tarzan's plans if he is successful in what he is attempting."
"What I can't understand," said Gregory, "is what has become of Helen, Brian, d'Arnot, and Lavac. Do you suppose they all went into the temple to help Tarzan?"
"They may have, or they may all have been recaptured. About all we can do is wait."
"Suppose we go on below Ashair and look for a hiding place. If we are between Ashair and the entrance to the tunnel, they will have to pass us to get out of the valley, for there is no other way out, so far as I know."
"I think you are right," agreed Gregory, "but I wonder if it will be safe to try to pass Ashair in the day time."
"Just as safe as it is to remain here at the mouth of this secret passage to their temple. Some of the Asharians may stumble upon us here at any time."
"All right," said Gregory, "let's try it. There are quantities of enormous lava blocks farther up at the foot of the escarpment. We may be able to make our way past the city and be entirely screened from it by them."
"Let's go," said Magra.
They made the laborious ascent to the jumbled pile of lava that had fallen from above; and though the going was rough, they found that they were entirely hidden from the city; and eventually came down again close to the lake well beyond Ashair.
Between them and the lake a low, limestone ridge shut off their view of the water. It paralleled the shore line, and extended for about a quarter of a mile, falling gradually to the level of the surrounding land. Upon its summit shrubs grew sparsely and a few gnarled trees. A rise of land hid it from Ashair.
"Look!" said Magra, pointing. "Isn't that a cave?"
"It looks like one," replied Gregory. "We'll have a look at it. If it's habitable, we're in luck, for we can hide there and keep a lookout for the others from the summit of the ridge."
"How about food?" asked Magra.
"I imagine we can find fruit and nuts in some of those larger trees just below the ridge," replied Gregory, "and if I have any luck at all I should be able to get a fish now and then."
As they talked, they approached the entrance to the cave, which, from the outside, appeared to be perfectly adapted to their needs; but they entered it cautiously. For a short distance only was the interior visible in the dun light that came through the entrance; beyond that they could see nothing.
"I think I'll explore a little before we settle down to light housekeeping," said Gregory.
"I'll go with you."
The cave narrowed into a dark corridor, which they followed, gropingly, in almost total darkness; but at a sharp turn it became lighter, and presently they came into a large cavern into which the sun poured through an opening in the roof. The cavern was large and grotesquely beautiful. Stalactites of various hues depended from ceiling and walls, while strangely shaped stalagmites covered much of the floor. Erosion had wrought strange limestone figures which rose like the creations of some mad sculptor among the tinted stalagmites.
"What a gorgeous spectacle!" exclaimed Magra.
"It is marvelous, and the coloring is beautiful," agreed Gregory, "but I think we should explore a little farther to make certain that it is a safe place for us to hide."
"Yes," said Magra, "you're quite right. There's an opening there at the far end of the cavern that may lead to something else. Let's have a look at it."
They found that the opening led into another corridor, dark and tortuous; and as they felt their way along it, Magra shuddered.
"There is something uncanny about this place," she whispered.
"Nonsense," said Gregory. "That's just because it's dark in here. Women don't like the dark."
"Do you?" she asked.
"Well, no; but just because a place is dark doesn't mean that it's dangerous."
"But," she insisted, "I have a feeling that we are being watched by unseen eyes."
"Oh, that's just your imagination, my dear child," laughed Gregory. "Your nerves are unstrung; and I don't wonder, after all that you have gone through. It's surprising that we're not all nervous wrecks."
"I don't believe that it's imagination," replied Magra. "I tell you I can feel that we are not alone. Something is near us. Something is watching us. Let's go back and get out of this terrible place. It's evil. I know it."
"Try and calm yourself, my dear," soothed Gregory; "there's no one near us; and anyway, if the place is evil, we want to know it."
"I hope you're right," said Magra; "but I'm still terrified; and, as you know, I'm not easily frightened. Here's an opening in the wall. It may be another corridor. Which one had we better take?"
"I think we'll keep right on in this one," replied Gregory. "It seems to be the main corridor. If we start turning off, we may become lost. I've heard of people being lost down in caves in Kentucky or Virginia or somewhere, and never being found again."
Just then a hand seized Magra from behind and whisked her through the opening they had just passed. Gregory heard a single piercing scream behind him, and wheeled about. To his horror, he found that he was alone. Magra had disappeared. He called her name aloud, but there was no reply; then he turned to go back and search for her. As he did so, another hand reached out from an opening on the opposite side of the corridor and seized him. He struggled and fought; but all his efforts were futile, and he was dragged into the darkness of a side corridor.