Suddenly space was snapping about him--they were off again. Another shock of surging energy--another--the ship leaped forward at tremendous speed--still greater--then they were rushing at top speed, and beside them ran the ghost ships of the _Ancient Mariner_. Morey pushed himself into the control room just as Arcot, Wade, and Fuller were getting ready to start for the lab. "We're off for quite a while, now," he said. "Our goal is about five days away. I suggest we stop at the end of four days, make more accurate measurements, then plan a closer stop. "I think from now on we ought to sleep in relays, so that there will be three of us awake at all times. I'll turn in now for ten hours, and then someone else can sleep. Okay?" It was agreed, and in the meantime the three on duty went down to the lab to work. Arcot had finished the installation of the invisibility apparatus in his suit at the end of ten hours, much to his disappointment. He tested it, then cast about for something to do while Wade and Morey added the finishing touches to theirs. Morey came down, and when Wade had finished his, which took another quarter of an hour, he took the off duty shift. Arcot had gone to the library, and Morey was at work down below. Fuller had come up, looking for something to do, and had hit upon the excellent idea of fixing a meal. He had just begun his preparations in the kitchen when suddenly the _Ancient Mariner_ gave a violent leap, and the men, not expecting any weight, suddenly fell in different ways with terrific force! Fuller fell half the length of the galley and was knocked out by the blow. Wade, asleep in bed, was awakened violently by the shock, and Morey, who had been strapped in his chair, was badly shaken. Everyone cried out simultaneously--and Arcot was on his way to the control room. The first shock was but a forerunner of the storm. Suddenly the ship was hurled violently about; the air was shot through with great burning sparks; the snapping hiss of electricity was everywhere, and every pointed metal object was throwing streamers of blue electric flame into the air! The ship rocked, heaved, and cavorted wildly, as though caught in the play of titanic forces! Scrambling wildly along the hand-holds, Arcot made his way towards the control room, which was now above, now below, and now to one side of him as the wildly variable acceleration shook the ship. Doggedly, he worked his way up, frequently getting severe burns from the flaming sparks. Below, in the power room, the relays were crashing in and out wildly. Then, suddenly, a new sound was added just as Arcot pulled himself into the control chair and strapped himself down. The radiation detector buzzed out its screaming warning! "COSMIC RAYS!" Arcot yelled. "HIGH CONCENTRATION!" He slapped at the switch which shot the heavy relux screens across every window in the ship.