Dark lenses were quickly donned. Tall peaks ahead burst into blazing pinpoints, their blinding splendor deepening the shadows beyond the on-rushing terminator to Stygian inkiness. Dazzling white crawled down the nearing spires and suddenly the sun's corona smote them like a blow with its glory. Abruptly they were in vivid sunlight. Peterson's ship still sped on before them. One hour; two; three. Crane chuckled: "Hell to pay if N.Y. is trying to raise Gates." "He's through," Bonwitt returned easily. "Fired; I'll bet." "Me, too. But, sa-ay! Look at that!" Crane flung up his arms against a glare that blazed suddenly through the forward ports. Directly ahead was a broad flat crater that shimmered in the sun's unobscured rays like a gigantic mirror of polished silver. "Mercury!" gasped Bonwitt. "A lake of mercury ten miles across. No one's ever reported _that_." "I'll bet Peterson knew about it. Look, he's circling." It was so. The engineer flung his little ship off toward the east to avoid detection. They speeded out of the sun's reflection from that lake of mercury. Its unrippled surface rose rapidly off starboard and was blotted out by the crater wall that enclosed it. Then the leading ship had landed. Bonwitt maneuvered to land in the shadow of a huge boulder. Clambering into their space-suits, they jumped the twelve feet to the powdery footing underneath. As easily as they'd have dropped two feet in earth gravity. Space-suited likewise, Peterson and Gates ducked into the dark opening of a cavern mouth. Bonwitt and Crane sneaked after them. Inside the cave entrance was instant, utter blackness. "Crane, where are you?" the engineer asked softly. For reply there came a crash as of the pinnacle of Proclus toppling on his helmet and a swirling burst of stars such as had never graced the firmament. After that, Bonwitt slipped into blackness. * * * * * He awoke with splitting head and a red film before his eyes. Two blurred figures were bending over him. He examined an egg-sized bump on his head with languidly exploring fingers. His helmet was off. The figures were those of Crane and Peterson. Damn! Bonwitt sat up jerkily and the effort set his head swimming and throbbing. The super was grinning his sardonic grin; Crane was grimacing a warning. "They've got us, old man," he said. "Might as well make the best of it. Here, let me help you up." With his aid, the engineer rose up and stood groggily swaying. Peterson, legs wide, bristly brows close, sneered at the big Earthman. "What'd you hit me with, a tractor? Or was it a meteor that fell?" grunted Bonwitt, gingerly fingering the lump on his head. Peterson's sneer relaxed. "Now you're using sense," he approved. "If you'da come up fighting it'da been just too bad for you."