Silently, the four men watched the two ships, waiting for any hostile movement. There was a long, tense moment, then something happened for which three of them were totally unprepared.

Arcot burst into sudden laughter.

"Don't—ho—hoh-ho—oh—don't shoot!" he cried, laughing so hard it was almost impossible to understand him. "Ohoh—space—curved!" he managed to gasp.

For a moment more, Morey looked puzzled—then he was laughing as hard as Arcot. Helplessly, Wade and Fuller looked at them, then at each other. Then, suddenly, Wade caught the meaning of Arcot's remark and joined the other two in laughter.

"All right," said Fuller, still mystified, "when you half-witted physicists recover, please let me in on the joke!" He knew it had something to do with the mysterious ships, so he looked closely at them in hopes that he would get the point, too. When he saw it, he blinked in amazement. "Hey! What is this? Those ships are exact duplicates of the Ancient Mariner!"

"That—that's what I was laughing at," Arcot explained, wiping his eyes. "Four big, brave explorers, scared of their own shadows!"

"The light from our own ship has come back to us, due to the intense curvature of the space which encloses us. In normal space, a light ray would take hundreds of millions of years to travel all the way around the Universe and return to its point of origin. Theoretically, it would be possible to photograph our own Galaxy as it was thousands of millennia ago by the light which left it then and has traveled all the way around the curvature of space.

"But our space has such terrific curvature that it only takes a fraction of a second for light to make the trip. It has gone all the way around our little cosmos and come back again.

"If we'd shot at it, we would have really done ourselves in! The ray beam would go around and hit us from behind!"

"Say, that is a nice proposition!" laughed Fuller. "Then we'll be accompanied by those ghosts all the way? There goes the spirit 'nine fathoms deep' which moves the ship—the ghosts that work the sails. This will be a real Ancient Mariner trip!"

It was like that famed voyage in another way, too. The men found little to do as they passed on at high speed through the vast realm of space. The chronometer pointed out the hours with exasperating slowness. The six hours that were to elapse before the first stop seemed as many days. They had thought of this trip as a wonderful adventure in itself, but the soundless continued monotony was depressing. They wandered around, aimlessly. Wade tried to sleep, but after lying strapped in his bunk for half an hour, he gave up in despair.

Arcot saw that the strain of doing nothing was not going to be good for his little crew and decided to see what could be done about it.

He went down to the laboratory and looked for inspiration. He found it.

"Hey! Morey! Wade! Fuller! Come on down here! I've got an idea!" he called.

They came to find him looking meditatively at the power pack from one of the flying suits he had designed. He had taken the lux metal case off and was looking at the neat apparatus that lay within.

"These are equipped for use with the space suits, of course," Morey pointed out, "and that gives us protection against gases. But I wonder if we might install protection against mechanical injury—with intent to damage aforethought! In other words, why not equip these suits with a small invisibility apparatus? We have it on the ship, but we might need personal protection, too."

"Great idea," said Wade, "provided you can find room in that case."

"I think we can. We won't need to add anything but a few tuning devices, really, and they don't take a whale of a lot of power."

Arcot pointed out the places where they could be put; also, he replaced some of the old induction coils with one of his new storage cells and got far higher efficiency from the tubes.

But principally, it was something to do.

Indeed, it was so thoroughly something to do that the six hours had almost elapsed before they realized it. In a very short time, they returned again to the control room and strapped themselves in.

Arcot reached toward the little red switch that controlled the titanic energies of the huge coil below and pulled it back a quarter of the way.

"There go the ghosts!" he said. The images had quickly disappeared, seemingly leaping away from them at terrific speed as the space in which the ship was enclosed opened out more and more and the curvature decreased. They were further away from themselves!

Easing back a quarter at a time, to prevent sparks again flying about in the atmosphere of the ship, Arcot cut the power to zero, and the ship was standing still once more.

They hurriedly dived to the observatory and looked eagerly out the window.

Far, far behind them, floating in the marvelous, soft, utter blackness of space, was a shining disc made up of myriads of glowing points. And it didn't seem to be a huge thing at a great distance, but simply a small glowing object a few feet outside the window.

So perfectly clear was their view through the lux metal wall and the black, empty space that all sense of distance was lost. It seemed more a miniature model of their universe—a tiny thing that floated close behind them, unwavering, shining with a faint light, a heatless illumination that made everything in the darkened observatory glow very faintly. It was the light of three hundred million suns seen at a distance of three million million million miles! And it seemed small because there was nothing with which to compare it.

It was an amazingly beautiful thing, that tiny floating disc of light.

Morey floated over to the cameras and began to take pictures.

"I'd like to take a color shot of that," he said a few minutes later, "but that would require a direct shot through the reflector telescope and a time exposure. And I can't do that; the ship is moving."

"Not enough to make any difference," Arcot contradicted. "We're moving away from it in a straight line, and that thing is three quintillion miles away. We're not moving fast enough to cause any measurable contraction in a time exposure. As for having a steady platform, this ship weighs a quarter of a million tons and is held by gyroscopes. We won't shake it."

While Morey took the time exposure, Arcot looked at the enlarged image in the telectroscope and tried to make angular measurements from the individual stars. This he found impossible. Although he could spot Betelgeuse and Antares because of their tremendous radiation, they were too close together for measurements; the angle subtended was too small.

Finally, he decided to use the distance between Antares and S Doradus in the Lesser Magellanic Cloud, one of the two clouds of stars which float as satellites to the Galaxy itself.

To double-check, he used the radius of the Galaxy as base to calculate the distance. The distances checked. The ship was five hundred thousand light years from home!

After all the necessary observations were made, they swung the ship on its axis and looked ahead for a landing place.

The nebulae ahead were still invisible to the naked eye except as points, but the telectroscope finally revealed one as decidedly nearer than the rest. It seemed to be a young Island Universe, for there was still a vast cloud of gas and dust from which stars were yet to be born in the central whorl—a single titanic gas cloud that stretched out through a million billion miles of space.

"Shall we head for that?" asked Arcot at last, as Morey finished his observations.

"I think it would be as good as any—there are more stars there than we can hope to visit."

"Well, then, here we go!"

Arcot dived for the control room, while Morey shut off the telectroscope and put the latest photographs in the file.

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.

There was a sudden crash and a fuse went out below—a fuse made of a silver bar two feet thick! In an instant, the flames of the burning sparks flared up and died. The ship cavorted madly, shaking mightily in the titanic, cosmic forces that surrounded it—the forces that made the highest energy form in the universe!

Arcot knew that nothing could be done with the power coil. It was drained; the circuit was broken. He shifted in the molecular drive, pushing the acceleration to four gravities, as high as the men could stand.

And still the powerful ship was being tossed about, the plaything of inconceivable forces. They lived only because the forces did not try to turn the ship more violently, not because of the strength of the ship, for nothing could resist the awful power around them.

As a guide, Arcot used the compass gyroscope, the only one not twisted far out of its original position; with it, he managed to steer a fairly straight course.

Meanwhile, in the power room, Wade and Morey were working frantically to get the space-strain drive coil recharged. Despite the strength-sapping strain of working under four gravities of acceleration, they managed to get the auxiliary power unit into operation. In a few moments, they had it pouring its energies into the coil-bank so that they could charge up the central drive coil.

Another silver bar fuse was inserted, and Wade checked the relays to make sure they were in working order.Fuller, who had regained consciousness, worked his way laboriously down to the power room carrying three space-suits. He had stopped in the lab to get the power belts, and the three men quickly donned them to help them overcome the four-gravity pull.

Another half hour sped by as the bucking ship forced its way through the terrific field in space.

Suddenly they felt a terrific jolt again—then the ship was moving more smoothly, and gradually it was calm. They were through!

"Have we got power for the space-strain drive yet?" Arcot called through the intercom.

"Enough," Morey cried. "Try it!"

Arcot cut off the molecular motion drive, and threw in all the space-control power he had. The ship was suddenly supercharged with energy. It jarred suddenly—then was quiet. He allowed ten minutes to pass, then he cut off the drive and allowed the ship to go into free fall.

Morey's voice came over the intercom. "Arcot, things are really busted up down here! We had to haywire half the drive together."

"I'll be right down. Every instrument on the ship seems to be out of kilter!"

It was a good thing they had plenty of spare parts; some of the smaller relays had burned out completely, and several of the power leads had fused under the load that had been forced through them.

The space-strain drive had been leaking energy at a terrific rate; without further repair, it could not function much longer.

In the power room, Arcot surveyed the damage. "Well, boys, we'd better get to work. We're stranded here until we get that drive repaired!"