He threw a somersault, lighted on his hands, and began to waltz about in the somewhat contracted space of the living-room of the projectile. Then he set up a loud shout as he regained his feet. "That's how!" he cried. The boys were alarmed. The man was evidently crazy, or perhaps he might be doing this for effect, in order to disarm their suspicions, so that he could discover Mr. Roumann's secret. They did not know what to do. "Come on, we'll all have a dance!" cried the man. "My name is Axtell--Fred Axtell. I used to live on the moon--tra-la-la!" His loud voice attracted the attention of Mr. Henderson, who was working at the far end of the shop. The professor ran toward the place where the strangely acting man was, the latter having now emerged from the ship, followed by the boys. "Here we go! Off to the moon!" cried the man, and catching up a big hammer he began to pound on the sides of the Annihilator as if he would destroy the projectile. CHAPTER X WASHINGTON IS AFRAID "Here! Here! Stop him! Grab that man!" cried Mr. Roumann, as he rushed toward Axtell, who was hammering away madly. Jack and Mark started for the fellow. "Keep away!" cried the machinist, swinging the sledge toward the boys. "I want to work on an airship, and I'm going to do it. I'll make some dents in it, and then I'll straighten them out! Whoop!" Mr. Henderson hastened forward. He took in the situation at a glance. "That man is insane!" the professor whispered to the German scientist. "Let me deal with him." "Do something quickly," pleaded Mr. Roumann, "or he will damage the projectile." "This is the way I work!" cried the insane man, and he brought down the hammer with great force on the rounded sides of the Annihilator. He made quite a dent in it. "Stop him!" begged Mr. Ronan. Mark and Jack had retreated out of reach of the big hammer, the professor and the German were consulting together, and in the door of the shop appeared Andy Sudds with his gun. He had gone away for a moment, in which interval the crazy machinist had appeared. "Andy will scare him with his gun," whispered Jack to Mark. Just then Mr. Henderson called out: "If you want work, I can give it to you." Axtell stopped his pounding of the projectile, laid his hammer down, and asked in a mild voice: "Can you give me work now?" "Of course," answered the professor, as if it was the most natural thing in the world to give work to insane persons. His calm manner and soothing words had a quieting effect on the lunatic. The glare died out of his eyes. "Come with me," went on Mr. Henderson. "I have some work outside." "What is it?" asked Axtell suspiciously. "I want you to dig a hole so we can put this airship in it," whispered the professor. "Come outside." He wanted to get the man out of the machine shop, where he could better deal with the fellow.