I walked at first slowly, then with ever-increasing confidence, for up from the surface streamed a guiding, a holding force, that was like a host of little invisible hands, steadying me, keeping firm my feet. I looked down; the myriads of enigmatic eyes were staring, staring up at me from deep within. They fascinated me; I felt my pace slowing; a vertigo seized me. Resolutely I dragged my gaze up and ahead; marched on. From the depths came more clearly the sound of the waters. Now there were but a few feet more of the bridge before me. I reached its end, dropped my feet over, felt them touch a smaller cube, and descended. Over the span came Ventnor. He was leading his laden pony. He had bandaged its eyes so that it could not look upon the narrow way it was treading. And close behind, a hand resting reassuringly upon its flank, strode Drake, swinging along carelessly. The little beast ambled along serenely, sure-footed as all its mountain kind, and docile to darkness and guidance. Then, an arm about Ruth, floated Norhala. Now she was beside us; dropped her arm from Ruth; glided past us. On for a hundred yards or more we went, and then she drew us a little toward the unseen canyon wall. She stood before us, shielding us. One golden call she sent. I looked back into the darkness. Something like an enormous, dimly shimmering rod was raising itself. Higher it rose and higher. Now it stood, upright, a slender towering pillar, a gigantic slim figure whose tip pointed a full hundred feet in the air. Then slowly it inclined itself toward us; drew closer, closer to the ground; touched and lay there for an instant inert. Abruptly it vanished. But well I knew what I had seen. The span over which we had passed had raised itself even as had the baby bridge of the fortress; had lifted itself across the chasm and dropping itself upon the hither verge had disintegrated into its units; was following us. A bridge of metal that could build itself--and break itself. A thinking, conscious metal bridge! A metal bridge with volition--with mind--that was following us. There sighed from behind a soft, sustained wailing; rapidly it neared us. A wanly glimmering shape drew by; halted. It was like a rigid serpent cut from a gigantic square bar of cold blue steel. Its head was a pyramid, a tetrahedron; its length vanished in the further darkness. The head raised itself, the blocks that formed its neck separating into open wedges like a Brobdignagian replica of those jointed, fantastic, little painted reptiles the Japanese toy-makers cut from wood. It seemed to regard us--mockingly. The pointed head dropped--past us streamed the body. Upon it other pyramids clustered--like the spikes that guarded the back of the nightmare Brontosaurus. Its end came swiftly into sight--its tail another pyramid twin to its head. It FLIRTED by--gaily; vanished.