The figure "1.41" was familiar enough. It was the square root of two, carried to two decimal places. But what was Jonner dividing by it, and why? He frowned in concentration. There was something familiar about the numbers, something that had to do with him and Jonner, and Jonner wouldn't be working arithmetic just for amusement. He saw Jonner moving on the horizon, just his head visible against the black sky, his body hidden by the curve of the planet. Jonner was circling. The sudden realization of danger wiped other thoughts from his mind. Until he saw the epitaph Jonner had written for Stein, Kraag had thought Jonner looked at this as he did: one man against the other, and winner take all. But Jonner intended to win even if he lost, because Jonner was not fighting just for Jonner's survival but for due process of law. Jonner was trying to make certain that, even if Kraag killed him, Martian law would punish Kraag for Stein's death. And if Jonner got into the sphere, he could get his message to Marsport or the rescue ship simply by turning on the radio. Kraag turned and raced back to the sphere. He arrived, panting heavily. Jonner was nowhere in sight, but he knew Jonner, circling, could not have gotten there ahead of him. He must kill Jonner before nightfall, if he could, but he must not get far enough from the sphere to let Jonner slip in behind him. He was not ready, yet, to destroy the radio to keep Jonner from it. He walked around the sphere. There was Jonner on the other side, only his head above the horizon, moving clockwise. The sun flashed and gleamed from Jonner's helmet. There was no sense in shooting at so small a target as a head. A mile away, Jonner's whole body was a small enough target. A carefully gauged leap carried Kraag to the top of the sphere. Here, 40 feet higher, his range of view was increased considerably. He could see Jonner well. Jonner could see him, too. Jonner stopped to hurl a stone. It took a while for the missile to cover the distance. It passed below Kraag's level, some distance away from him. "Why don't you give it up, Jonner?" asked Kraag. "You can't hurt me with a rock, at this distance." "Why should I?" retorted Jonner. "All I have to do is wait till night." "Sure, wait. But I'm not waiting, Jonner. One of us is going to win this thing before night, or I'm going to blast the radio so you can't reach Marsport. If I have to do that, I'll track you down tomorrow--and I think I can stay outside and fight you away from the sphere tonight." "Getting desperate enough to fight like a man now, aren't you, Kraag? If you want a showdown today, I'm willing."