Smaller machines came rolling forward under the big tracks of the larger. They came boldly to the barrier of up-thrust steel girders set in cement to stop the passage of any machine. Then from these smaller machines came thin, tubular tentacles. Lances of flame hissed from the tubes and the steel girders began to fall, cut at their bases by oxy-hydrogen torches. Artillery began to roar, the guns served and aimed by hand. Windows shattered in the blastings, and great gaping holes opened the ranks of the machines. But more machines came out of the water, raced forward and backed up the first line of advance. Long tubular cases pointed--and the next artillery piece exploded as the lanyard was pulled. Nor, after that, could any man move one bit of steel against another. The girders started to fall once more. * * * * * Then men went forward, carrying timbers like battering rams. They hit one machine and had their ram jerked from their grasp and hurled into the air behind the line of machines and attacked them with fists. Like lightning, the mechanical girders danced back and forth, the grapples closing on man after man and lifting him out of the way. Each soldier was passed back over the head of the machine to another, and one after another they left the scene of the battle and were transported, still struggling, far to the rear. The advance into the enclosure was inexorable. Harry Vinson turned to the girl and shook his head. "Licked," he said bitterly. "It wants--us," said Narina helplessly. Vinson hurled the metal cube to the floor. "It's going to get us, too," he said. He turned from the scene outside and faced her. "Narina," he said softly, "you're aces." She looked up at him and a weary smile crossed her face. "How wrong we were--about you." He nodded. "Too bad we didn't find it out sooner." Narina shook her head bitterly. "So that this could have happened sooner? Why?" "Maybe if we had been busy together, we would not have spent time building bigger and better machines against one another. Another thing, Narina, our machines are equipped with all we know about fighting and weapons. Had there been no strife--?" A rumble came at the base of the building. Narina shuddered. "It's coming for us," she said in a whisper. "For what?" Narina shrugged. She leaned forward and took his hand. "I don't know," she said. "But this is the end of it all. God! How sweet it could have been--" Narina's arms went up around him; she fondled the back of his head gently and pulled his face down to hers. He caught her to him and her response was swift. But it was not complete--nor was his--for the rumbling increased and its warning roar intruded upon the stolen moment of sweetness.