"Suppose we go out and take a look around it," proposed Mark. "Ned and Sam will know if any intruder has been sneaking around there." They all went out where the Annihilator was in process of building, but the machinists said they had not been disturbed, and they were sure no one had stolen anything. There was no further disturbance that night, but when Mr. Roumann paid an early visit to the machine shop the next morning, he uttered a cry of surprise. "What is it?" asked Jack, who accompanied him. "The plates--the plates of the Etherium motor!" cried the scientist. "They have been stolen!" CHAPTER IX A CRAZY MACHINIST For a moment Jack stared at Mr. Roumann. He did not appreciate the seriousness of the announcement. The scientist was hurrying here and there, looking under benches and on tables for missing plates. "Do you mean the plates that make the motor go?" asked Jack. "No, not those, but the plates from which the mysterious force is projected into space--the plates that give the forward motion to the projectile. They have been stolen. They were taken last night, and the man Andy fired at stole them!" "Will that prevent us from making the trip?" "No. I have duplicate plates." "Then little harm is done." "No particular harm is done to the projectile, but I am afraid that, with the plates in his possession, the man may discover the secret of the power that I use. Oh, I should have locked them up, but I thought they would be safe." "What has happened?" asked Mr. Henderson, entering the machine shop at that moment. The scientist told him, and expressed his fear. "Do you really think there is any danger that the man, whoever he was, will learn how to use the plates?" inquired the professor. "Perhaps, and then, again, perhaps not. I think it will be very difficult for him to work out the secret of the power from the plates, for they are only a small part of the mechanism. Still, he may do so. I am convinced now that this man is either the same one of whom I stand in fear, or he is some one hired by him to steal my secret." "Then we had better notify the police," suggested Mark. "No, that would never do," answered Mr. Roumann. "I would have to describe the plates, in order to have the authorities identify them in the possession of the thief, and I do not care to do that. No; the best plan will be to hasten work or the Annihilator, and start for Mars before the thief can gain any advantage from the plates. If he should succeed in discovering from the plate how to make the power that is discharged in wireless currents, it will take him a long time, and we can be away before then. Let us hasten our work and start for Mars." "You say you have duplicates of the plates?" asked Jack. "Yes. I was afraid lest something happen to one set, so I made three. Well, it will do no good to worry, but I wish I had the plates back."