Then he went on at a pace Chet found difficulty in following, until they came to a place where Towahg tore a vine aside to show easier going, but climbed instead over a fallen tree, grown thickly with vines, and here even Chet could see that other feet had tripped and stumbled. The Master Pilot glanced at the triple star still pinned to his blouse; he thought of the study and training that had preceded the conferring of that rating, the charting of the stars, navigational problems in a three-dimensional sea. And he smiled at his failure to read this trail that to Towahg was entirely plain. * * * * * "Every man to his job," he told the black, and patted him on the shoulder, "and you know yours, Towahg, you're good! Now, where do we sleep?" He ventured to suggest a bed of leaves that had gathered amongst a maze of great rocks, but Towahg registered violent disapproval. He pointed to a pendant vine; his hands that were clumsy at so many things gave an unmistakable imitation of a bud that developed on that vine and opened. Then Towahg sniffed once at that imaginary flower, and his body went suddenly limp and apparently lifeless as it fell to the ground. "You're right, old top!" Chet assured him, as Towahg came again to his feet. "This is no place to take a nap." A crashing of some enormous body that tore the tough jungle in its rush came from beyond the rocks. "And there are other reasons," he added as he followed Towahg's example and leaped for a hanging tangle of laced vines. Here was a ladder ready to take them to the high roof above, but they did not need it; the crashing died away in the distance. It was Chet's first intimation that this section of the Dark Moon held beasts more huge than the "Moon-pigs" he had killed: it was a disturbing bit of knowledge. He caught Towahg's cautious, wary eyes and motioned toward the branches high overhead. "How about hanging ourselves up there for the night?" he asked, and the gestures, though not the words, were plain, as the ape-man's quick dissent made clear. * * * * * He motioned Chet to follow. Down they plunged, and always down. Towahg gave Chet to understand that Kreiss had slept some distance beyond: they would try to reach the same place. But the quick-falling dusk caught them while yet among the black rubbery trees. And the dark showed Chet why their branches might not be inviting as a sleeping place. By ones and twos they came at first, occasional lines of light that flowed swiftly and vanished through the black tangle of limbs. Chet could hardly believe them real; they appeared and were lost from sight as if they had melted. But more came, and it seemed at last as if the roof above were alive with light. The moving, luminous things glowed in hues that were never still: were pure gold, were green, then red, melting and changing through all the colors of the spectrum.