Then I remembered. The vertical green wall that soared above me as I lay dazed from Jim's blow. The translucent green wall in whose depths I had seen the blind fish rushing toward me. Water! The sea! Impossible! There were scientific miracle-workers in the enemy's ranks, but they couldn't have hollowed out a pit such as this in mid-ocean; forced back the very ocean to create this amphitheatre, this dry plain on the Atlantic's very bottom: held back the unthinkable weight of Earth's waters by a nothingness. Incredible! Yet the accomplished fact stared me in the face. My eyes traveled up that impossible wall. It must have been at least six hundred feet high. At its summit, in a murky haze that heaved and billowed, I made out strange, dim bulks that hung, unsupported. A long line of them, a long ellipse following closely the curving of the cliff. Underneath the nearest, barely perceptible, I could make out a lens-shaped cage of wire. I began to understand. Overarching everything was a great dome of heaving cloud. "_Smirn-ow!_" The long line snapped into immobility. "By the left flank, march!" We were moving, marching. Then my ruse had succeeded. I had chosen the right cave number. I breathed a sigh of relief. * * * * * The command for route order was given, and at once a buzz of talk broke out around me. "Damn them, they're sending us right off to work! We missed our mess, hunting for that damned spy. But that don't mean anything. It's back to the tunnel for ours." "Oh, quit your bellyaching, Andreyeff. Another week, and we'll be in New York. Just think of it, the richest city in the world to loot! And women! Why, they tell me the American women are to the Frenchies and the cold English-women as the sun is to the stars. What's a meal more or less when you think of that?" An obscene laugh swept through the ranks. Guttural voices boasted of past exploits--black deeds and sadistic cruelties that had marked the trail of the hordes sweeping over Europe from the windy Asiatic steppes. As we marched, I noticed a peculiarity of the rocky floor. There were no sharp edges, no sudden cleavages in the uneven terrain. It looked, for all the world, as though the stone had been melted, then frozen again in a moment. An unbelievable pattern was forming itself in my mind. If what I thought were true--! The command came to halt. We had reached the blazing disk I had seen from afar. It was a tremendous shaft, dropping straight into the very bowels of the earth. Two hundred feet across, a blinding glare streamed up from the pit. From far beneath came shoutings, the clank of machinery, a growling roar.