He learned, amongst other things, what seemed the origin of the worship of the Serpent, Quetzalcoatl, amongst primitive Mexican races. The time had been when the People of the Temple had mingled freely with the races above them; and, that they might have ready means of egress to the world, they had built the tunnel through which Kirby had entered the Valley of the Geyser. Thus, going and coming as they did, they had spread their cult of the worship of Quetzalcoatl; and when, eventually, strife arose between the peoples of upper world and lower, and the People of the Temple withdrew to their realm, they left behind them the Serpent myth which was to live through countless centuries. The tunnel, Naida said, had been abandoned when her people left the upper world once and for all, and its use for any reason prohibited. This, Naida gave as the reason why none of them went near the tunnel now, and why the cylinder of gold had lain in the canyon undiscovered. It was the explanation she had promised on the day in the tower, when first she saw the cylinder. So the days passed, until the day set aside for wedding and coronation dawned. On that morning, Kirby, having concluded a long conference with the Duca, was walking with Naida in the gardens outside the castle. "Tell me," he said to her: "do you yourself believe that this Serpent has the powers of a God?" Naida looked at him quickly, a sudden fright in her eyes. "I believe the Serpent exists to-day, somewhere in the distant reaches of the chasm, beyond the Rorroh forest." "Yes, but do you believe the Serpent is God?" * * * * * Actually frightened now, she looked swiftly about. But when she saw that they were alone, confidence returned. "No!" she exclaimed. "I do not believe Quetzalcoatl is a god. I believe he is the most terrible creature anywhere in our realm, and that men first worshipped him through fear. I believe our race would be better a hundred times if they had never made him their God." Kirby whistled. "Then you do _not_ believe that the Ducas of past ages talked with him. You do not believe it was Quetzalcoatl's pleasure over the great diamond which made him cease preying on your people?" "No! Long habit makes me show respect for these myths, and adhere to the customs of our cult, but I do not believe. I think our race gained immunity for the Serpent's ravages, not through a compact with Quetzalcoatl, but because our builders were intelligent enough to erect the castle up here on the plateau, where Quetzalcoatl could not reach them. To tell the truth, I think the whole cult is false and wrong, and I wish Quetzalcoatl were dead and gone from the world!" Kirby smiled. In spite of Naida's reverence for certain features of the cult, he had long suspected that her true feelings were those she had just expressed. And he was glad for this new bond of understanding between them. He glanced at her with understanding and perfect trust.