"Here, what's the trouble?" the boys heard a constable ask as he shouldered his way into the throng. "This fellow tried to snatch this lady's purse and run away with it," explained one of the men who had grabbed the scoundrel. "Stand still, you brute!" he shouted at him, "or I'll shake you to pieces! Such fellows as you ought to go to the whipping-post!" "I'll take charge of him," announced the officer. "Who is he? Does any one know?" "Stranger in town, I guess," volunteered the other man, who had helped capture him. "Need any help, officer?" "No, I guess I can manage him. Come along now, and behave yourself, or I'll use my club. It hasn't been tried on any one yet." "That's one of the new constables, I guess," said Mark, and Jack nodded. The crowd separated to allow the officer to take out his prisoner. As the latter walked forward in the grip of the constable, he remarked in a mild voice totally at variance with his bold act: "Why, I only wanted a little change to pay my fare to the moon. I'm going there to look for my brother." "Crazy as a loon," said one of the men. "Or pretending that he is," added the officer. "Mark!" cried Jack, pointing at the prisoner, "look!" "The man who held me captive!" gasped Mark. "And he's wearing my clothes yet! But he's in custody now, and we needn't fear any more from him." "Unless he gets away," said Jack. "We'll go tell the chief who he is, and he'll keep him safe," suggested Mark, and they hurried to headquarters, reaching there just before the prisoner was brought in. The boys were assured by the chief that the man, who was evidently a dangerous lunatic, would be kept where he could do no harm. He would be arraigned later on the serious charge of attempted highway robbery, as well as of being a dangerous lunatic at large. When the boys and Andy got back, they found the two professors and Washington still going over the machinery in detail. "Find anything wrong?" asked Jack, after they had told of the arrest of Axtell. "No, but we will have another look in the morning," said Mr. Henderson. "Then, if we find nothing out of order, I think we will take a chance and start." A thorough inspection by all hands the next day did not disclose anything wrong, and, a test of the motors and other machinery having shown that it was in good working shape, it was decided to leave the earth. "At last, I think, we are really going to get under way to the moon," said Jack, as he closed the big main door. This time it was not reopened. All the stores and supplies were in place. The two professors were in the engine room. Washington White was in his galley, getting ready to serve the first meal in the air. Jack and Mark were in the pilot house, ready to do whatever was necessary and anxious to feel the thrill that would tell them the projectile had left the earth. "All ready?" asked Professor Henderson. "All ready," replied his German assistant. "Then here we go!" announced the aged scientist.