"A little innovation of mine, to make things more interesting," said Jonner. "In case you ever want to use the idea, I made me a super-slingshot out of two of the jeep inner tubes from the cargo, and a couple of crowbars I could drive into crevices. Fixed it up yesterday for bombardment purposes." The duel went on. There came the time when the hammer of the pistol clicked on an empty chamber. "How do you refuel this thing, Jonner?" asked Kraag pleasantly. The sun was still high. He could retreat to the interior of the sphere and figure it out if he had to. "It's pretty hard to do with spacesuit hooks," replied Jonner. "Be glad to demonstrate, if you'll toss me the gun." Kraag laughed, a laugh with more triumph in it than humor, because in his fumbling he had just hit the button that ejected the magazine. To push in a fresh one was the matter of a moment. He had hoped Jonner would move in closer when he knew the pistol was empty, but no such luck. Jonner stayed put. Kraag's first effort with the new magazine brought no results, for he had neglected to prime the weapon by pushing the outer covering back on the barrel. He did this, and resumed his methodical firing. As the time wore on, Kraag began to appreciate the difficulties involved in hitting a moving target, even a slowly moving one, when the marksman was as inexperienced as he was. The trouble was that, at that distance, he could not see where the bullets were striking and had no way of knowing how wide of his mark he was shooting. He was on the fourth magazine and the sun had passed the meridian when he felt the sphere vibrate faintly and momentarily beneath him. He twisted around, alarmed. He could see nothing. It wasn't one of Jonner's rocks, because a big one had just missed. His eye detected a shining streak that stretched a few inches along the curve of the sphere's meteor shield, at about the level of his feet. He bent to examine it. Something had struck it at high speed, a glancing blow. It couldn't be one of Jonner's rocks. Small meteor? A jagged hole suddenly appeared in the observatory dome near him. Kraag moved up and examined it closely. It had been made by some small object. Through the glassite he could see a similar hole in the other side of the dome. Did Jonner have some sort of new weapon? He couldn't. Even Jonner wasn't resourceful enough to invent a high-powered weapon with the innocuous cargo they were carrying for the Titan colony. Something struck Kraag a powerful blow in the left chest, a blow that hurled him sideways, to tumble off the sphere and fall slowly to the ground below. There was a great pain in his chest, and he released his hand-hooks in agony, so that the pistol fell away from him. Kraag gasped for breath as he struck the ground and bounced. He coughed up blood. He fell slowly again, and bounced again. The third time he settled jarringly, prone on his back.