That day saw several thousand more miles reeled off on the journey to the moon, and that evening (or rather what corresponded to evening, for it was perpetual daylight) they began to make their preparations for landing. Their wonderful journey through space was nearing an end. "I guess that crazy Axtell fellow was only joking when he said we'd never reach the moon," ventured Jack. "Nothing has happened yet." "Only the meteor," said Mark, "and he couldn't know about that. I guess he didn't get a chance to damage any of the machinery." "No, we seem to be making good time," went on his chum. "I think I'll go and----" Jack did not finish his sentence. Instead he stared at one of the instruments hanging from the walls of the engine room. It was a sort of barometer to tell their distance from the earth, and it swung to and fro like a pendulum. Now the instrument was swinging out away from the wall to which it was attached. Further and further over it inclined. Jack felt a curious sensation. Mark put his hand to his head. "I feel--feel dizzy!" he exclaimed. "What is the matter?" "Something has happened," cried Jack. The instrument swung over still more. Some tools fell from a work bench, and landed on the steel floor with a crash. The boys were staggering about the engine room, unable to maintain their balance. There came cries of fear from the galley, where Washington White was rattling away amid his pots and pans. Andy Sudds was calling to some one, and from the pilot-house came the excited exclamations of Professors Henderson and Roumann. "We're turning turtle!" suddenly yelled Jack. "The projectile is turning over in the air! Something has gone wrong! Perhaps this is the revenge of that crazy man!" and, as he spoke, he fell over backward, Mark following him, while the _Annihilator_ was turned completely over and seemed to be falling down into unfathomable depths. CHAPTER XVIII AT THE MOON Confusion reigned aboard the _Annihilator_. It had turned completely over, and was now moving through space apparently bottom side up. Of course, being cigar shaped, this did not make any difference as far as the exterior was concerned, but it did make a great difference to those within. The occupants of the great shell had fallen and slid down the rounded sides of the projectile, and were now standing on what had been the ceiling. Objects that were not fast had also followed them, scattering all about, some narrowly missing hitting our friends. Of course, the machinery was now in the air, over the heads of the travellers. This was one of the most serious phases of the accident, for the great Cardite motor was built to run while in the other position, and when it was turned upside down it immediately stopped, and the projectile, deprived of its motive power, at once began falling through space. "What has happened? What caused it?" cried Mark, as he crawled over to where Jack sat on the ceiling, with a dazed look on his face.