class="c2"/>

The bald-headed scientist pulled himself to the ampliscope. But it was possible to see the object through the ports now, quite plainly. It was black, cylindrical, glinting dully in the sun's light. The space ship was tumbling end over end, lazily, bringing the thing into view first at one port—then another.

"No acceleration!" Kass reported, amazement mingling with hope. "Same speed—we may still hit—but no evidence of gravity. We're falling toward it on momentum alone!"

Lents' brown eyes twinkled with perplexity in their pits of fat.

"The force, whatever it is, doesn't seem like anything in nature. But if we're traveling on momentum alone we can pull away with our emergency rockets—though I hate to waste the fuel."

Sine leaped to the rocket controls. "Grab handholds!" he snapped over his shoulder. The men rolled into the padded niches provided for that purpose. Sine's niche was so placed that it would not be necessary to lift a hand against the tremendous pressure of rocket acceleration. A lateral swing of the lever along its quadrant operated the rockets.

"Oof!" came a smothered exclamation from Lents as the ship seemed to pause, to leap forward in space again. The star-studded heavens as seen through the ports were hidden by a curtain of flame, electric blue and as stiff seeming as a steel bar—the trail of the forward rockets.

For some minutes there was no sound save the subdued thunder of the hull as it trembled under the tug of the rockets. Then a light flashed redly and a gong sounded. The signal that meant, "fuel half gone." Sine shut off the power, crawled out stiffly. His first glance out of a port showed that they were still falling toward the mysterious cylindrical space wanderer.

Kass wiped the sweat from his bald head.

"No use wasting any more effort," he said hoarsely. "That thing is a space ship, and there are men in it. The force they have been using on us is some kind of gravity beam—probably it's also their means of space propulsion. They mean to capture us, no doubt——"

"And they've reversed the beam!" Lents puffed as he turned away from the ampliscope, pulling his sweat-soaked toga away from his fat body with thumb and forefinger. "We're decelerating fast, but we can't feel it because the force acts on every particle of our bodies exactly the same as on the ship——"

"Proving," added Sine, looking out of the port curiously, "that it's a true gravity beam!"

The utter stillness of their ship gave the illusion that she was motionless, and that the sinister stranger was drifting toward them.

"It is a ship!" Lents rumbled. "Look at her ports. But they're shuttered."

"Not a bad idea," Sine agreed. "Protection against pin-point meteorites, anyway." They saw now that the cylinder was slightly rounded at each end, and the end presented to them had at its nose a circular projection, not unlike a very large button, that glowed with a lavender light, which they guessed to be the source of the gravity beam.

They were torn between the excitement of discovery and a very natural apprehension. In the dim past, more than 200,000 years ago, there had been a regular commerce between Earth and the Jovian colonies. But the comet swarm, coming out of the mysterious depths of space, had released to the solar system such swarms of meteorites as to make interplanetary travel in the spatial belt between Mars and Jupiter utterly suicidal. It required the passing of two thousand centuries to thin them out sufficiently to permit the voyage of exploration in which these three men were engaged.

What would these children of Earth look like after 200,000 years of Jovian evolution? Would they be friendly?

They must, at any rate, be curious people. The great cylinder was passing over them, and they had a better conception of its size. It was at least twice as big as the 200-foot diameter Kass had estimated, and fully 1500 feet long. A section of its hull slid open, and the scientists felt the tug of mysterious forces on their own little vessel. They drifted up into the opening, knew that the hatch had closed by the shutting out of the solar glare. But there was no lack of light. They could see the welded plates of the hull by an intense saffron light that came from oval plates set in the wall. More of the gravity buttons were ranged around the room. It appeared that they were regularly used in handling freight. Now, as the little captive ship was tugged here and there, the prisoners could see flashes of that penetrating lavender light that seemed somehow solid.

"Get ready, men!" Sine said, breaking off his absorbed contemplation of their surroundings. "Strap on your belts, and be sure your disintegrator tubes are in their clips."

Lents was already lifting his toga and snapping his weapon belt around his ample waist. A mere strip of flexible metal with pockets for the atobombs and a clip for the delicate little tube—it might easily be taken for a mere ornamental article of apparel.

"Hope they're friendly," Kass remarked, patting the buckle shut over his flat diaphragm, "but if they aren't we can give 'em a thing or two to think about."

The quartz ports, kept free from frost on the inside by a curtain of hot dry air blown over them through a slit, suddenly misted over on the outside, became opaque with a milky glaze of frost. This told the prisoners that their captors were "bleeding" air into the hold, which did double duty as an airlock. They heard vague clanging of metal on metal, transmitted to them through the hull of their ship. Then a sharp blade scraped away the ice from one of the ports, and a face peered in.

They looked at one another for a few moments, these cousins of the human race, separated by 200,000 years of time and impassable meteor-strewn wastes of space. The man at the port turned and beckoned to others, who also surveyed the prisoners.

Then the first one, evidently the chief of this massive space vessel, motioned to the prisoners, to open their manports.

"Keep together now!" Sine admonished his companions. "If they act unfriendly we'll let them have the ray. Then you two slip back into your own ship while I grab this vacuum suit out of the lock. With that on I can carve a way out, and disable them, too."

"It would be a shame!" Kass said as he whirled the handwheel of the inner manport, "but——"

The valve opened, and a few minutes later the three Earthmen stepped out to confront the Jovians.

There were half a dozen of them, standing firmly, by virtue of the artificial gravity, somehow produced. They were not far different from Earthmen, except that they were shorter, being barely five feet tall. Their tremendous muscles told of the race's adaptation to the superior gravity of Jupiter. Their feet, encased in slippers of some burnished material, were unusually large.

They were dressed in an armor of overlapping scales that covered every part of their bodies, even their fingers. But their heads, instead of being armored, were protected by a thin, transparent membrane that followed the shape of their features closely. The Earthmen recognized the protective covering used before the comet swarm as a defense against the then used heat ray. So the Jovians had developed no new weapon! Sine thought comfortably of his little disintegrator tube. He could make those armored men vanish like puffs of smoke.

But they made no hostile move, and Sine had leisure to notice their faces. If their bodies were too heavily muscled for grace, their heads atoned for that defect. These were truly Jovian, god-like, combining intense virility, dominance, courage. But there was also about them an expression of intolerance, of ruthlessness, of selfishness. Here were men, it could be seen, who would not be too scrupulous in attaining their ends. But men, too, who could be charming companions.

Their leader, the man who had first looked into the port, now detached himself from the group and came forward, his hand outstretched