A great wave of indignation swept over Steve Rush. He was so angry that, for the moment, he nearly forgot his prudence. His first inclination was to shout at the man over there sawing away so industriously. But the boy quickly realized the foolishness of doing any such thing. His purpose was to capture the man. There would be time enough to cry out after he had done that. "Who could do such a thing?" Steve muttered, beginning to rise a little higher in the water as he took wide strokes, driving himself along at as great a speed as was possible. Steve permitted himself to drift around the side of the abutment, so that he might climb up to it as far away from the man as possible. Otherwise the scoundrel might get the advantage of him. Steve's cunning was worthy of an Indian. At last the boy's fingers grasped the edge of the abutment. He pulled himself up slowly, allowing the water to drip from him little by little as he rose from the river. Right beside him was a flat-bottomed punt moored to an iron pillar. It was in this that the man had gotten out. Steve rose and listened; then, hearing no sound, he made his way over the cement and pieces of piping that littered the surface of the abutment. He was bothered by hearing no sound. He wondered if the man had discovered his presence. "I must be cautious," thought the boy. "I shall get myself into a fix, and perhaps have the whole structure down on me if I don't look sharp." A sound to the right of him caused Steve to straighten up suddenly. He saw the figure of a man approaching him. "Stand still. I've got you!" cried the boy. At the same instant he sprang forward. He was not afraid to tackle the man. What he feared was that the fellow would get away from him before the boy got a chance to down him. Steve's leap carried him within three feet of his prey. The Iron Boy was preparing to strike out hard, when something was swung in a half circle about the head of the other man. The object was the metal saw that the fellow had been using for his nefarious purpose. It caught Steve a blow on the side of the head, lifting the boy from his feet sideways and dropping him to the abutment. As he fell, Rush, who was not knocked senseless, fastened about the ankles of his enemy with both arms. The result of this move was that the man went over too. He toppled over backwards with Steve holding to him tightly. In an instant the two were fighting desperately. Blows were struck on both sides; breaths came short and sharp. All at once the support slipped from beneath them and the two fighters rolled over into the river, where the battle was continued with renewed vigor. But Rush had been weakened somewhat by the blow from the metal saw and was not at his best. "You villain!" he shouted. "I've got you now. I've----"