But Ralph shook his head. "We'll probably have only a few hours of air to spare, Diane. If we both look, we'll cover more ground. I hate to ask you, because it won't be pretty out there. But it might be our only chance." "I'll go, of course. Ralph?" "Yes?" "What is this sargasso, anyway?" * * * * * He shrugged as he read the meters on the compressed air tanks. Four tanks full, with ten hours of air, for two, in each. One tank half full. Five hours. Five plus forty. Forty-five hours of air. They would need a minimum of thirty-five hours to reach Mars. "No one knows for sure about the sargasso," he said, wanting to talk, wanting to dispel his own fear so he would not communicate it to her as he took the spacesuits down from their rack and began to climb into one. "They don't think it's anything but the ships, though. It started with a few ships. Then more. And more. Trapped by mutual gravity. It got bigger and bigger and I think there are almost a thousand derelicts here now. There's talk of blasting them clear, of salvaging them for metals and so on. But so far the planetary governments haven't co-operated." "But how did the first ships get here?" "It doesn't make a hell of a lot of difference. One theory is ships only, and maybe a couple of hunks of meteoric debris in the beginning. Another theory says there may be a particularly heavy small asteroid in this maze of wrecks somewhere--you know, superheavy stuff with the atoms stripped of their electrons and the nuclei squeezed together, weighing in the neighborhood of a couple of tons per square inch. That could account for the beginning, but once the thing got started, the wrecked ships account for more wrecked ships and pretty soon you have--a sargasso." Diane nodded and said, "You can put my helmet on now." "All right. Don't forget to check the radio with me before we go out. If the radio doesn't work, then you stay here. Because I want us in constant radio contact if we're both out there. Is that understood?" "Yes, sir, captain," she said, and grinned. It was her old grin. He had not seen her grin like that for a long time. He had almost forgotten what that grin was like. It made her face seem younger and prettier, as he had remembered it from what seemed so long ago but was only three years. It was a wonderful grin and he watched it in the split-second which remained before he swung the heavy helmet up and in place over her shoulders. Then he put on his own helmet awkwardly and fingered the outside radio controls. "Hear me?" he said. "I can hear you." Her voice was metallic but very clear through the suit radios. "Then listen. There shouldn't be any danger of getting lost. I'll leave a light on inside the ship and we'll see it through the ports. It will be the only light, so whatever you do, don't go out of range. As long as you can always see it, you'll be O.K. Understand?"