"They found, as our observations had shown us, that Triton had a good atmosphere, and that it was swarming already with many forms of life, some of them unutterably grotesque, and none of more than the lowest intelligence. Using weapons of concentrated force-rays, which clove through all they touched, our millions of Neptunians proceeded to annihilate all life upon Triton, and with that accomplished, proceeded to build for themselves structures and cities like those on Neptune. They found that Triton was a perfectly habitable world for them save for two considerations. One of these was the lesser gravitational power of it, which made it extremely inconvenient for them to move on it with their Neptunian muscles. They solved this problem by attaching to their limbs small and unobtrusive disks of an extremely heavy metal which we could make by the artificial massing of atom-protons without electrons. These disks increased their weight to such a point that they could move as freely and conveniently on Triton as on Neptune. "The other problem facing them on Triton was the fact that it turned one face always toward the sun. Its rotation on its axis, indeed, was of just enough speed to counteract its revolution around Neptune and Neptune's own revolution around the sun, the sum total of its movements resulting in this keeping of one side always toward the sun, with that side always palely lit by the sun and the other always in darkness. Even when Triton was behind Neptune, invisible perhaps from your own world by reason of the edge of Neptune's great atmosphere projecting up to hide it somewhat, Triton's orbit was so slanted or inclined toward the plane of the solar system that the sun was always in sight of its sunward side, though dimmed a little when the edge of Neptune's atmosphere was between them. The Neptunians who had gone to Triton were accustomed to Neptune's alternating day and night, of approximately ten hours each, and so they solved the problem by living upon the sunlit side of Triton for ten hours, for a day, and then passing to the dark side for ten hours of night.