"This was the dastardly plot he evolved," said Professor Roumann. "He slipped this magnet into the equilibrium machine, knowing that in time it would cause a deflection of the delicate needles, and so shift the centre of gravity. He must have done this as a last resort, and to provide for his revenge in case we discovered him on board after we started. It was a cruel revenge, for had I not discovered it we would soon all be killed." "Is the machine all right now?" asked Jack. "It will be in a few minutes. Here, take this magnet and put it as far away from the engine room as possible." It was the work of but a few minutes, now that the disturbing element was removed, to readjust the gravity machine, and Mr. Roumann called: "Look out, now, everybody! We're going to turn right side up again!" As he spoke he turned a small valve wheel. There was a clanging of heavy ballast weights, which slid down their rods to the proper places. Then, like some great fish turning over in the water, the _Annihilator_ turned over in the ether, and was once more on her proper keel, if such a shaped craft can be said to have a keel. Of course, the occupants of the space ship went slipping and sliding back, even as they had fallen ceilingward before, but they were prepared for it, and no one was hurt. From the galley came a chorus of cries, as pots and pans once more scattered about Washington, but there was no more soup to spill. As soon as the _Annihilator_ was righted, the Cardite motor began to work automatically, and once more the projectile, with the seekers of the moon, was shooting through space at their former speed. They had lost considerable distance, but it was easy to make it up. "Well, that _was_ an experience," remarked Jack, as he and his chum began picking up the tools and other objects that were scattered all about by the change in equilibrium. "I should say yes," agreed Mark. "I'm glad it didn't happen at dinner time. That fellow Axtell is a fiend to think of such a thing." "Indeed, he is! But we're all right now, though it did feel funny to be turned upside down." An inspection of the projectile was made, but they could discover no particular damage done. She seemed to be moving along the same as before, and, except for the upsetting of things in the store-room, it would hardly have been known, an hour later, that a dreadful accident was narrowly averted. Washington made more soup, and soon had a fine meal ready, over which the travellers discussed their recent experience. "And when do you think we will arrive?" asked Jack of Mr. Henderson. "We ought to be at the moon inside of two days now. We have not made quite the speed we calculated on, but that does not matter. I think we will go even more slowly on the remainder of the trip, as I wish to take some scientific observations." "Yes, and so do I," added Mr. Roumann. "I think if we make fifteen miles a second from now on we will be moving fast enough."