"After we have eaten and rested," said Herkuf, "I'll go and see if the boat is still where I hid it. That was many years ago; but it was well hidden, and it is seldom that anyone comes to this part of the valley. I sank it in a tiny inlet beneath bushes that overhung the water."
"It has probably rotted away by this time," suggested Helen.
"No, I think not," replied Herkuf. "It would only rot if exposed to the air."
As they ate the broiled fish, they discussed their plans and recalled the adventures through which they had passed; and Helen asked Herkuf how it had been possible to construct the temple at the bottom of the lake. "That seems to me," she said, "an engineering feat far beyond the capabilities of the Asharians, for nothing else that they have accomplished, as far as I have seen, suggests more than a primitive knowledge of engineering. With the exception of these diving helmets, I have seen nothing that indicates great inventive genius, either."
"It was the invention of the diving helmet, coupled with a natural phenomenon, that made it possible to build the temple," explained Herkuf. "We are a very ancient race. We have occupied the valley of Tuen-Baka for perhaps three thousand years. Our origin is legendary, but it is believed that our early ancestors came down from the north, bringing with them a well developed civilization and considerable engineering knowledge. There were two factions or tribes. One settled at what is now Thobos, the other at Ashair. It was an Asharian who invented the diving helmet. He was always puttering around with metals and chemicals, trying to make gold from common substances; and during his experiments, he accidentally discovered a combination of chemicals that, when water was poured on them, generated air that could be breathed; but he had a sad end just as he was about to transmute a black powder he had compounded into gold. All that was necessary, he believed, was to apply great pressure suddenly; so he placed a little of it on a piece of lava and struck it with a hammer. There was a terrific noise and much smoke; and the roof blew off the inventor's house, and he went with it. One of his assistants, who miraculously escaped death, saw it all. But, though he did not succeed in making gold, he left behind him a great invention in the form of the diving helmet, which was thoroughly perfected and in common use, though more for sport than for any practical purpose."
"But what had that to do with the building of the temple?" asked Helen.
"I am coming to that. Off shore from Ashair, at the point above where the temple now stands, the water was always in constant turmoil, a jet of it often flying into the air fifty or a hundred feet with a great hissing sound. The origin of this phenomenon was a mystery which the Asharians would have liked to solve; so, one day, a venturesome youth donned a water suit and helmet and set forth on the bottom of the lake to investigate. He was gone about half an hour, when watchers on the shore saw him shoot up, above the surface of the water at the spot where the phenomenon occurred. By a miracle, he was not killed; and when he finally came back to shore, he reported that a great geyser of air was shooting up from a hole in the bottom of the lake.
"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 Ashar-ians 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."