"I have fixed you," the letter began. "You will never get to the moon. I shall have my revenge. You took my brother Fred Axtell to Mars and left him there. I determined to get him back, and to that end I disguised myself as one of the boys, and got aboard. When we were safely away from the earth, I would have compelled you to go to Mars and rescue my brother. But my plan has failed. I will have my revenge, though. You will never reach the moon, even if you do get started. Beware! George, the brother of Fred Axtell, will avenge his fate!" "The brother of the crazy machinist!" gasped Jack. "Now I understand his strange actions. He's crazy, too--he wanted to go to Mars--he says we will never reach the moon! Say, look here!" cried Jack, raising his voice. "Here's bad news! That scoundrel has put some game up on us! Maybe he's tampered with the machinery! It won't be safe to start for the moon until we've looked over everything carefully! He says he's fixed us, and perhaps he has!" From the projectile came hurrying the would-be moon travellers, a vague fear in their hearts. CHAPTER XIV OFF AT LAST In the gathering twilight Professor Henderson read slowly the note Dick had brought. Then he passed it to Professor Roumann. The latter shook his shaggy gray hair, and murmured something in German. "Where did you meet the man?" asked Jack of the young motorcyclist. "About two miles down the road. He was walking along, sort of talking to himself, and I was afraid of him. He called to me, and offered me a half a dollar to deliver this message. I didn't want to at first, but he said if I didn't he'd hurt me, so I took it. Is it anything bad?" "We don't know yet," replied Mark. "No, that is the worst of it," added Professor Roumann. "He has made a threat, but we can't tell whether or not he will accomplish it. We are in the dark. He may have done some secret damage to our machinery, and it will take a careful inspection to show it." "And will the inspection have to be made now?" asked Jack. "I think so," answered Professor Henderson gravely. "It would not be safe to start for the moon and have a breakdown before we got there. We must wait until morning to begin our trip." "It will be the safest," spoke the German, and the boys, in spite of the fact that they were anxious to get under way, were forced to the same conclusion. "Then if we're going to camp here for the night," proposed old Andy, "what's the matter with me and the boys having a hunt for that man? We've put up with enough from him, and it's time he was punished. If we let him go on, he'll annoy us all the while, if not now, then after we get back from the moon. I'm for giving him a chase and having him arrested." "He certainly deserves some punishment, if only for the way he treated Mark," was Jack's opinion, his chum having related how he was drugged and kept a prisoner in the secret room, and how he escaped in time to unmask the villain.