Presently she saw ahead of them a small circular building topped by a single dome, and realized that it was toward this the ptomes were leading her. When they reached the building, which seemed to have neither doors nor windows, two ptomes seized Helen's arms, one on either side, and leaped lightly upward, carrying her with them, the third ptome following. A few swimming strokes carried them to the top of the dome, where the girl saw a circular door, which she recognized now, from the gadgets flanking it, as the entrance to an air chamber such as that through which she had passed from the temple to the lake bottom.
The chamber below was filled with water when they entered it, and it was several minutes before it emptied; then the ptomes removed her helmet and suit, lifted a trap door in the floor, pointed to a ladder, and motioned her to descend. As in the upper chamber, there was a window in the wall on the side opposite to that from which they had approached the dome, which she had previously thought windowless; and through this window the diffused light of the lake bottom dimly illuminated the interior of the circular room in which she was imprisoned. It was entirely bare—the walls, the window, and the ladder constituted her world. The ptomes had closed the trap door above her, and presently she heard water gushing into the chamber above; then it commenced to trickle down one wall of her prison, and presently the trickle became a little stream. As water covered the floor of her cell, she understood the nature of the torture and death that confronted her. The chamber would fill slowly. She might prolong life and agony by climbing the ladder, but the end was inevitably the same.
She realized what exquisite mental torture the minds of these people had conceived, that one should be condemned to die alone, drowned like a rat in a trap. She wondered if she would have the courage to end it quickly when the water was deep enough, or if she would drag out the torture to the topmost rung of the ladder.
And as the water rose slowly in Helen's death cell, Herkuf whispered to Tarzan through the bars of his cage, "It will soon be time. Do you think you can do it?"
"I can do my part," the ape-man assured him. "When the time comes, let me know."
When night came and darkness settled above Horus a faint light still filtered down through the waters to the death cell where Helen waited for the end. It was the light of heavenly stars, but it brought no hope of the doomed girl. The water was at her knees now; and she stood with one hand on the ladder, still wondering what she should do. She turned wearily; and, with both arms resting on a rung of the ladder, buried her face in them. She thought of d'Arnot and the happiness that might have been theirs had they met under different circumstances; and, even with hope gone, that thought made her want to cling to life as long as she could, for at least there was a certain sad happiness in envisioning the happiness she had been denied. She thought of Brian; and, without bitterness toward him, she execrated the avarice that had lured him to this awful place and cost the lives of so many people, people who loved him. And she prayed.
Again Herkuf whispered to Tarzan. "It is time," he said. "They will all be asleep. But the bars are very strong."
"Not so strong as Tarzan," replied the ape-man. "I have tried them— watch!"
As he spoke, he seized two bars. The muscles stood out upon his shoulders as he exerted his strength upon the insensate metal. Herkuf watched, breathless, and filled with doubt; then he saw the bars spreading apart, and a moment later saw Tarzan squeeze between them and push them back into place. Similarly the ape-man liberated Herkuf.
"You are as strong as a bull elephant," gasped the priest.
"Come!" said Tarzan. "We have no time to waste. Lead the way."
"No," replied Herkuf, "we have no time to waste. Even if we get through without delay, we may still be too late."
Silently, stealthily, Herkuf and Tarzan crossed the temple toward a closed door. The other prisoners slept. No one had seen Tarzan escape and release Herkuf. Even the bars, bent back almost to normal position, gave little evidence of the manner of their liberation; and few would have believed the truth, for many have been the prisoners who had sought to bend them; but never before had it been done.
Herkuf led Tarzan down a short corridor to the room of the ptomes; and as the priest opened the door, Tarzan saw the lesser priests sleeping on their hard benches. He saw their water suits hanging on their pegs and their tridents in the racks. The ptomes slept thus without sentries and the temple went unguarded because it was considered impregnable.
Cautiously the two men took three water suits and helmets from their pegs, gathered up three tridents, and crossed the room to the doorway on the opposite side without awakening a ptome. Once past the door, each donned a suit.
"The gods have been with us so far," whispered Herkuf, "and if we can pass through the air chamber without being discovered, we stand a good chance to succeed—if we are in time."
As the water rose to Helen's shoulders she finally gave up all thought of suicide. She would cling to life to the last moment. They might rob her of that; but they could not rob her of her courage, and as the water rose still higher she stepped to the lowest rung of the ladder.
Reminiscences rioted through her mind as she waited for death, and pleasant thoughts and bitter. She pondered the futility of man's quest for sudden wealth and of the evil and suffering it entailed. Of what avail would success be now to either Brian or Thorne if, by some chance, it should come to one of them? for one had lost his sister and, perhaps, his father; and the other had lost his mind. Now the water forced her up to a higher rung of the ladder. Step by step, she was climbing to her rendezvous with Death.
Herkuf and Tarzan passed safely through the air chamber out into the water of the lake. Through the garden of the ptomes they made their way toward the watery cell where Death was creeping relentlessly upon Helen Gregory, and dark shapes glided sinuously about them in this mysterious world of silence.
At last they reached the air chamber above Helen's cell; and Herkuf started the pump that would eject the water, but it seemed to both men that it would never empty the chamber. They knew that the water had been rising for hours in the death cell beneath them and that death might come to the girl before they reached her, if she were not already dead.
Just below them, clinging to the last few precious moments of life, Helen had ascended the ladder as far as she could go; but the water pursued her relentlessly. Already her head was touching the ceiling. She could climb no farther. The cold hand of Death caressed her cheek. Suddenly she became alert, listening. She heard noises in the chamber above. What might they signify? Not rescue, certainly; perhaps some new torture.
At last the air chamber was emptied. Tarzan and Herkuf attempted to raise the trap door leading into Helen's cell; but it defied their every effort, even the Herculean strength of the Lord of the Jungle. And what was happening, or had happened, in the cell below?—cell or tomb?
And while Tarzan and Herkuf labored with the trap door a ptome awoke and sat up upon his hard bench, rubbing his eyes. He had had a strange, disquieting dream in which enemies had passed through the room of the ptomes. He looked about to see if anyone was there who should not be. Mechanically, he looked for his water suit and helmet. They were gone, and two other pegs were empty. Instantly he awoke his fellows and disclosed his discovery, telling them of his dream. They were all much perturbed, for such things had never happened before in the memory of man. They started to investigate immediately, going first to the throne room, where they soon discovered that two of the prisoners were missing.