"It seems to me that we're rather outnumbered." I said. "And it's rather more pleasant in here than outside." "I'm going to get that rifle," Ray declared, "and give these big crabs a little respect for humanity!" "Let's rest up a while first, anyhow," I urged. * * * * * Presently Mildred noticed how tired we were. She went into the third of the connected cylinders of blue crystal, was busy a few minutes and called us to the couches she had prepared there. "You may sleep," she told us. "The Things never come here. And they said they would not harm you, if you did not try to go out." We lay down on the silken beds. In a few minutes I was sleep. I awoke to feel a curious unease, a sense of impending catastrophe. Ray was bending over me, his face drawn with anxiety. "Something's happened!" he whispered. "She's gone!" I sat up, staring into the liquid blue vastness of the tall cylinder above us. "Listen! What's that?" A deep bell-note sounded out, brazen, clanging. Sonorous, throbbing, mighty, it rang through the cylindered rooms. Slowly it died; faded to silence with a last ringing pulse. Tense minutes of silence passed. Again it boomed out, throbbed, and died. After more long minutes there was yet a third. "Outside, somewhere!" Ray started; ran to the arched door. We looked out upon the dense forest of gold and crimson mushrooms that grew below the black cavern roof. Before us, across a few hundred yards of bare rocky beach, was the edge of the crystal lake with the city of blue cylinders upon its floor. "God! What's that?" Ray gripped my arm crushingly. A thin wailing scream came across the beach from the black lake. A piteous sound it was, plaintive, pleading. Higher and higher it rose, until it was a piercing silver note. Clear and sweet it was, but inexpressibly lonely, sorrowful, mournful. It sank slowly, died away. Again it rose and fell, and again. "It's Mildred!" I gasped. "Didn't she say something about singing to the crabs?" "Yes! I think she did. Well, if that's singing, it's wonderful! Had me feeling like I'd never see another human. But listen--" * * * * * Liquid, trilling notes were rising, pealing out in a queer, swift rhythm. It was happy, joyous, carefree. The rippling golden tones made me think of the caroling of birds on a spring morning. Swiftly it rose and fell, pure and clear as the tinkle of a mountain brook. Mildred sang not words but notes of pure music. The gay song died. And the strong clear voice rose again with the force and challenge of bugle notes, with a swift marching time beating through it. It throbbed to a rhythm strange to me. It set my feet tingling to move; it set my heart to pulsing faster. It was a challenge to action, to battle. Unconsciously obeying the suggestion of the song, Ray whispered, "Let's get over and see what's going on."