"If it is ruined, Nat can pay for it," said Dave, firmly. "I'll pay for nothing!" grumbled the boy who had done the mischief. He was short of spending-money, and knew how hard it was to get an extra dollar from his parent. "He certainly ought to pay for it," said Caspar Potts. "Some men would have him locked up for what he has done." "Humph! Don't talk foolish! It was only a little fun!" grumbled Nat. "I didn't mean any harm. You can easily get those spots out of your clothes." "Did he do anything else to you?" asked Dave of the professor. "Yes, he plagued me a good deal, and he shoved me down in the cow-yard," was the reply. "I was hoping some one would come to drive him away. I said I'd have the law on him, but he laughed at me, and said nobody else was around and his word was as good as mine." "If that isn't Nat to a T!" murmured the senator's son. "Doing the sneak act every time!" "Well, we are witnesses against him," put in Phil. He looked at Dave and suddenly began to grin. "Oh, but this is great!" he cried. "What's struck you?" queried Dave. "Oh, nothing, only I reckon we've got a good hold on Mr. Aaron Poole now--in case he tries to make a complaint against you." "To be sure we have!" burst out Roger. "He won't dare to do it--after he knows what Professor Potts can do." "What are you talking about?" demanded Nat, curiously. "Is my father going to make a complaint against Dave? What is it for?" "Maybe you'll learn later--and maybe you won't," answered the senator's son. "But if you see your father you had better tell him to call it off as far as Dave is concerned--if he wants to save you." "Then you've had trouble, eh?" "No worse than this--if as bad." "Humph! In that case my father won't believe what you say about me!" cried Nat, cunningly. And then of a sudden he leaped back, turned, and ran around a corner of the barn at top speed. He made for the road, and was soon hidden from view by trees and bushes. Phil and Roger attempted to catch him, but Dave called them back. "No use in doing that," said Dave. "Let him go. It will be time enough to say more when Mr. Poole makes his complaint." The three youths assisted Caspar Potts in rearranging his toilet, and in the meantime the aged professor told the lads the details of his trouble with Nat. The money-lender's son had certainly acted in a despicable manner, and he deserved to be punished. "I will leave the matter to Mr. Wadsworth, and to your father and your uncle," said Professor Potts to Dave. "They will know better what to do than I." On the way back to the Wadsworth mansion the boys told of the pistol incident and the professor became much interested. He agreed with Phil and Roger that Nat's doings were much worse. Dave's father and his uncle had returned, and the youth went straight to them with his tale. Then Mr. Wadsworth came in and was likewise told. All the men were also informed of what had happened to Caspar Potts.