His voice sounded a little queer and squeaky over the wire, and for the matter of that so did Zaidie's as she replied: "Yes, I'm ready, I think. I hope these things will work all right." "You may be quite sure that I shouldn't have put _you_ into one of them if I hadn't tested them pretty thoroughly," he replied, swinging the door open and throwing out a light folding iron ladder which was hinged to the floor. They were in the shade cast by the hull of the _Astronef_. For about ten yards in front of her Zaidie saw a dense black shadow, and beyond it a stretch of grey-white sand lit up by a glare of sunlight which would have been intolerable if it had not been for the smoke-coloured slips of glass which had been fitted behind the glass visors of the helmets. Over it were thickly scattered boulders and pieces of rock bleached and desiccated, and each throwing a black shadow, fantastically shaped and yet clearly defined on the grey-white sand behind it. There was no soil, and all the softer kind of rock and stone had crumbled away ages ago. Every particle of moisture had long since evaporated; even chemical combinations had been dissolved by the alternations of heat and cold known only on earth to the chemist in his laboratory. Only the hardest rocks, such as granites and basalts, remained. Everything else had been reduced to the universal grey-white impalpable powder into which Zaidie's shoes sank when she, holding her husband's hand, went down the ladder and stood at the foot of it--first of the earth-dwellers to set foot on another world. Redgrave followed her with a little spring from the centre of the ladder which landed him with strange gentleness beside her. He took both her gloved hands and pressed them hard in his. He would have kissed his welcome to the World that Had Been if he could, but that of course was out of the question, and so he had to be content with telling her that he wanted to. Then, hand in hand, they crossed the little plateau towards the edge of the tremendous gulf, fifty-four miles across and nearly twenty thousand feet deep, which forms the crater of Tycho. In the middle of it rose a conical mountain about five thousand feet high, the summit of which was just beginning to catch the solar rays. Half of the vast plain was already brilliantly illuminated, but round the central cone was a semicircle of shadow of impenetrable blackness. "Day and night in this same valley, actually side by side!" said Zaidie. Then she stopped and pointed down into the brightly lit distance, and went on hurriedly, "Look, Lenox; look at the foot of the mountain there! Doesn't that seem like the ruins of a city?" "It does," he said, "and there's no reason why it shouldn't be. I've always thought that, as the air and water disappeared from the upper parts of the moon, the inhabitants, whoever they were, must have been driven down into the deeper parts. Shall we go down and see?" "But how?" she said.