Kirby, hard headed to the last, drew from the supply in one pocket of his tunic, a strip of one of the tuberlike roots, and munched it. The thunder ceased. The waters receded. After that Kirby hesitated not a second. Promptly he moved forward, flung his coil of line down into the geyser tunnel, and swung on to the line. By the time he had swallowed the last bite of his breakfast, the world he knew had been left behind, and he was climbing down to a new. * * * * * It became at once apparent that the gorgeously colored, glassy-smooth throat glowed with tints which were unfamiliar to him. He could perceive these new shades of color, yet had no name for them. As he stopped after fifty feet to breathe, the color phenomenon made him wonder if the tuber roots he had been eating had affected his vision; then decided they had not. In addition to food value, the roots had some power to stimulate courage and a slight mental exhilaration. But the drug had proved non-habit forming, and Kirby knew that his powers of perception were not now, and never had been, affected. He swung down further. Just a moment after he began that progress was when things began to happen to him. First he heard what seemed to be the low titter of a human voice laughing sweetly. Next came a far off, unutterably lovely strumming of music. And then he realized that, at a depth of about a hundred feet, he was hanging level with a hole which marked the mouth of another tunnel. This new tunnel sloped down into the earth on his right hand. The floor and walls were glassy smooth, and the angle of descent was steep, but by no means as steep as the drop of the vertical geyser shaft in which he now hung. Laughter, music, the new tunnel suddenly aroused an excitement which made him quiver. "When I saw _her_," he gasped, "she was standing here, in the mouth of this tunnel, looking up at me!" Violently, Freddie Kirby forgot the maple-shaded street of his Kansas town, forgot everything but desire to reach the mouth of the new tunnel, where the girl of the exquisite face and beckoning lips had stood. Tightening his grip on the rope, he began to swing himself back and forth like a pendulum. It seemed probable that when the geyser water shot up past the horizontal tunnel, its force was so great that no water at all entered. He redoubled his efforts to widen his swing. * * * * * Then his feet scraped on the floor, and in a second he had alighted there. He still hung stoutly to his line, however, for the tunnel sloped down sharply enough, and was slippery enough, to prohibit the maintenance of footing unaided. The music which issued from the depths of that stunningly mysterious passage swelled to a crescendo--and stopped. Kirby clung there to his precarious perch, his feet slipping on the glass under them with every move he made, and feelings stirred in his heart which had never been there before.