Clatclit was slowing his pace and moving more carefully. Then, not ten feet in front of him, the fiery glow of his tail tip was reflected from a million foaming, shifting wet surfaces. He took another few courageous steps, then halted, pressed back against the curve of the tunnel wall. He'd averted his gaze from the raging torrent beyond him, but his outstretched hand still pointed in that direction. I felt a cold wet spray on my face, and saw, with a little shock, that some of the glittering facets of Clatclit's scaly hide were already becoming pocked and eroded. "We'll have to go fast," I said, releasing Snow's hand only to clutch her arm tightly against my side. "If we take too long, our luciferous friend here will be a sticky red puddle. And I don't intend crossing that in the dark!" "_That_" was a jagged ridge of rock that continued forward from where our segment of tunnel ended, scant feet beyond Clatclit's cowering form. It was glistening with pools of black water and wet froth, flung up there by the raging river that passed less than a foot beneath its slightly arched surface. The torrent rushed angrily from somewhere in the hollow blackness to our right, leaped and sprayed past the natural bridge of rock, barely two feet wide, that lay before our feet, and then-- My stomach grew sick at the sight just to the left of the bridge. The vaulted tunnel which contained this black Martian river dipped and dropped. The river, just beyond our frail bridge, was a black cataract falling into the heart of the planet. "Jery," Snow said, shivering. "Hold me. Hold me tight, or I'll never get across that!" "It's all right," I said, with a calm tone that surprised the hell out of me. "Here." I got directly behind her and ran my hands along the undersides of her forearms, gripping them tightly midway to her wrists. "Now, just walk as I direct you, Snow. Close your eyes if you want. I won't guide you wrong." "I trust you, Jery," she said softly. "Okay then, honey." I kept my voice gentle, soothing. "Left foot forward. No, a bit more. There! Okay, now the right foot." She swayed a little in my grasp, on the first slippery section of that dangerous arch of rock. "Easy! That's it, honey, you're doing fine. Now your left. Ah! Okay. And then the right. Swell." Step by nightmare step, we crossed the arch, Snow moving her feet blindly forward in exploratory shuffles, and I, forgetting my own danger in my concern for her, moving steadily with her, eyeing each spot on that rock ahead of her feet for safety. The light grew dimmer by the minute as we crept further and further from Clatclit. I wondered how long I could have stood in a spray of liquid caustic or acid, holding a light for some friends. Then the last step was made, and without my knowing how it happened, Snow was tightly in my arms, facing me now, her silky hair against my cheek, her arms locked about my waist.