"Three or four hundred miles, over country like we've been crossing in the last week, with a girl! Ray, we'd never make it!" "It's the only chance." I said nothing more. I knew that I could stand no such march on my frozen feet, but I resolved to say nothing about it. I would help them as far as I could, and then walk out of camp some night. Men have done just that. Mildred brought out sacks of the little cakes, and of a red powder that seemed to be the dried and ground flesh of a crimson mushroom. We made a pack for each of us, as heavy as we could carry. * * * * * Just before we were ready to start Ray took off my footgear and treated my feet from his medicine kit. I had feared gangrene, but he assured me that there was no danger if they were well cared for. Walking was still exquisitely painful to me as we slipped out through the arched door and into the fungoid forest beyond the three blue cylinders. As rapidly and silently as possible we hastened through the brilliant fungous forest, across the river of opalescent liquid, to the foot of the fall of fire. A weird and splendid sight was that sheer arc of shimmering white flame, roaring into a pool of opal light, and surrounded with a mist of moon-flame. We reached the foot of the metal ladder spiked to the rocks beside the fall and started up immediately. The going was not easy. The packs of food, heavy enough when we were on level ground, were difficult indeed to lift when one was scrambling up over rungs four feet apart. Ray climbed ahead, with a piece of rope fastened from his waist to Mildred's, so that he could help her if she slipped. I was below the girl. We were halfway up the rock when suddenly a glare of red light shone upon me, casting my shadow sharply on the cliff. I looked up and saw the broad, intensely red beam of a heat-ray like that we had seen the giant crab use. The ray came, evidently, from the shore of the great lake with its submerged city of blue cylinders. It fell upon the face of the cliff just above us. Quickly the ladder was heated to cherry red. The face of the rock grew incandescent, cracked. Hot sparks rained down upon us. Slowly the ray moved down, toward us. "Guess we'd better call it off," said Ray. "They have the advantage right now. Better get to climbing down, Jim. This ladder is going to be burning my hands pretty soon." * * * * * I climbed down. Mildred and Ray scrambled down behind me. The ray followed us, keeping the metal at a cherry red just above Ray's hands. I looked down and saw a dozen of the giant crabs lumbering up out of the fungoid jungle from the direction of the great lake. Hideous things they were, with staring, stalked eyes, shining green antennae, polished red shells, claw-armed limbs. Like the one that had passed us in the upper cavern, they wore glistening white metal accoutrements. We clambered down, with the red ray following.