He was quickly bound with ropes, and placed in the storeroom as a prisoner, while the German turned his whole attention to the motor, a part of which had been broken. Once more the Annihilator had ceased to advance, and was falling through space. "Can you fix it?" anxiously asked Jack, who was panting from the terrible struggle. "Yes," replied Mr. Roumann. "Fortunately he did not smash a vital part. I will soon have it running again." In less than half an hour the motor was repaired, and was speeding the projectile on its way. It was not set at the greatest power, however, as Mr. Roumann did not want to put too much strain upon it. "Now I have time to inquire how it happened," he said to the boys. "Tell me about it." They related how they had come upon the crazy machinist. "Then he has been hidden on board all the while," commented the German. "I was not mistaken in thinking some one opened that port after I closed it. He sneaked in here the night before we started, and has been waiting his chance to do us some damage. It was he who smashed the plates." "But where could he have concealed himself?" asked Jack. "I don't know. We'll see if he will tell us." They went to the storeroom, where the maniac was bound. "Why did you try to damage my machinery?" asked Mr. Roumann. "Because it is an infringement on my patent," was the surprising answer. "I invented a perpetual motion machine, for making dog biscuits, and you have used it to make your airship go. Therefore I smashed it. I have the sole right to make dog biscuits for the king of the cannibal islands. I'm his private secretary." "He is hopelessly insane," murmured Jack. "I fear so," agreed Mr. Roumann. Then he asked: "Where have you been hiding?" "Ah, I fooled you, all right," said the man with a cunning laugh. "It was just like a game of hide and seek to watch you hunting for me, and me looking at you all the while. Ha, ha! Oh, I had a good place." "Where was it?" asked Mr. Roumann soothingly. "Right up there," answered the machinist, pointing to the roof of the storeroom. The German made an investigation, and discovered a small compartment where it had been intended to make a port, but the idea for which had not been carried out. This left a space in the wall of the projectile, large enough for a man to conceal himself in. No one would suspect he was there. "I sneaked on board one night," went on the man. "I managed to open a port into the storeroom. And I lived high, I can tell you." "Golly! He's been at mah kitchen stuff!" exclaimed Washington. "Did that other man come aboard with you?" asked Jack. He referred to the tramp who had peered in the window of the professor's house. "No. He's been elected King of France," was the answer. "He had to go over there to get his crown fitted on. I'm all alone here. A few minutes more and I would have smashed that engine."