Front matter (continued 2)

The consciousness we had of that great ray's existence and the knowledge we had of the doom it was loosing upon the peoples of our world served to prevent the dream-like lassitude of our conditions from overpowering us, and we were further awakened by the swift expansion of Saturn, ahead, as our flier neared it. For by then the great faceted ball of our flier was hurtling on through the void at five million miles an hour, slowly approaching the limits of its speed as our mighty rear force-ray drove us forward with tremendous power. And at that speed, in the next three days, Saturn loomed larger and larger ahead, until we saw at last that upon the fourth day's beginning we would pass the mighty planet. And at that our interest rose to excitement, because we would pass closer by Saturn than any of the planets in our straight flight out to Neptune, passing it indeed by no more than a million miles. So that as the last hours of those three days passed, we observed the big, yellow-glowing disk of Saturn ahead with intense interest.

And a strange sight indeed was great Saturn as it loomed greater before us and to the left, for strangest of all the sun's planets to the eye is this one. Greatest of all the planets save for mighty Jupiter, its huge sphere seemed even greater than Jupiter by reason of the colossal rings that encircled it, and by its nine greater moons that revolved about it. A solar system in itself seemed Saturn, indeed, its huge rings tilted somewhat, those great rings themselves tens of thousands of miles in width and thousands of miles from the planet they encircled. We could see, as we drew nearer toward the great planet, that those rings were in fact what had long been known by Earth's astronomers—gigantic flat swarms of meteorites and meteoric material revolving about the great planet at immense speed. Of the surface of Saturn, though, no more could be seen than of that of Jupiter, since like Jupiter the great planet was wreathed in colossal cloud-belts.

Marlin shook his head as he gazed toward the great ring-girdled planet, almost filling the heavens beside us. "It is well for us that Saturn is not our goal," he said. "Those titanic meteoric masses that are the rings—to blunder into them would mean instant annihilation."

Whitely nodded. "As it is," he said, "there must be many meteors in this region about Saturn—many that have broken loose from the rings or are flying toward those rings."

"Let's hope that you're wrong on that, at least," I told him. "We'll soon be passing within a million miles of those rings, and I want to meet no meteorites—not after our experience with the asteroids."

By then, indeed, we had drawn almost level with Saturn, its huge sphere and colossal rings almost directly to the left, the edge of those rings, but a half-hundred miles or less in thickness, being a scant million miles or more from our racing space-flier. The great maze of the planet's nine greater moons seemed crowded now upon its other side from us, Titan, largest of those moons shining brilliantly as a small white disk near the huge yellow bulk of Saturn and its colossal rings. Before then indeed, I had been forced to shoot out from the flier's side a force-ray toward Saturn, to counteract the great planet's pull upon us, but though it loomed beside us now almost as immense as great Jupiter itself, its recorded pull upon us was many times less. This was due, I knew, to the comparatively small mass of Saturn, since though of immense size and possessing a vast atmosphere, it is known to be the least dense of all the planets, being of less than 0.7 the density of water.

Even so, however, it was requiring a force-ray of great power to hold our rushing flier out from the huge planet. Though lesser than Jupiter's, its pull upon us was great, nevertheless. And now that we were passing the huge world so closely, it seemed to us with its vast rings and great family of whirling moons to be of universe-size itself, so mighty did it loom beside us. The great rings, of small thickness compared to their huge width and circle, were edge-on to us now, a million miles to the left, and we could see that they were in reality but vast swarms of countless meteors, great and small, whirling at great speed about Saturn and forming by their division three rings, the innermost a darker one. Yet despite their strange appearance and colossal size, it was not the great rings that held our interest so much in that moment as the cloud-hidden surface of Saturn itself. For even as in passing Mars and Jupiter, we were gripped with desire to veer in toward the planet and explore the strange wonders that might exist upon it, or upon its greater moons. But none suggested that thought now. All four of us knew that only the growing green spot of light, that was distant Neptune ahead, must be our goal.

As the flier raced on, almost passing the huge planet now, Randall uttered a swift exclamation, pointing ahead and to the left a little. At the same moment, though, I had seen the thing that had caught his eye—a small dark point growing with lightning swiftness as it rushed toward us; a great dark meteor, perhaps five hundred feet in diameter, rushing toward our flier, whirling far out from Saturn's rings in the same direction as those rings! Instantly, upon seeing it, I had turned more power into the ray that held us out from Saturn, and as we were pushed sidewise in the next moment by that increased power, the big meteor had flashed past us far to the left! And a moment later, I had caught sight of two similar meteors, one smaller than the other, rushing toward us in the same direction from ahead. But these I had seen soon enough to avoid collision.

It was evident that, as Whitely had suggested, we were encountering some of the stray meteors that might be expected to whirl here far out from the meteor-swarms of the great rings. And as we watched tensely now for more meteors, it was with something of awe that we gazed toward the huge rings, that we knew to be rushing swarms of countless similar meteors. It was well, as Marlin had said, that we were not called upon to penetrate through or around those great rings, since in their awful whirling swarms of meteors no craft would be able to live even for a moment. But our space-flier was passing the midmost point of those rings; already huge Saturn was beginning to drop a little behind us; and we breathed more freely. And, ironically enough, it was at that very moment of our relief that catastrophe came upon us. There was a wild shout from Marlin, and simultaneously I saw a huge round dark mass looming dead ahead and whirling toward us. Just as I snapped open the control-levers, that great dark meteor's mass had struck our onrushing flier with a tremendous stunning shock!

For an instant, as the flier reeled and spun there crazily in the gulf of space, it seemed the end to me, but in a moment more I realized that the great faceted walls had not been penetrated, for the air in the flier was unchanged. Had those walls been pierced, the result would have been the instant freezing to death of all of us. But that death had not as yet come upon us, and as I struggled forward in my chair I saw that the space-flier was still whirling crazily around from the shock and that the throbbing of its great generators had ceased. Beside me Marlin and Whitely and Randall were coming back to realization of their surroundings after that colossal shock, Whitely bearing a nasty cut upon his temple. And as Marlin sprang to the flier's side-window, gazed obliquely from it, he uttered an exclamation.

"That meteor just grazed us!" he exclaimed. "If you hadn't jerked the controls over at the last moment, Hunt, it would have hit us head-on! As it is, it smashed through the flier's outer wall, but didn't pierce the inner wall!"

"But the generators!" cried Whitely, who had been fumbling at their switches. "They've stopped! When the meteor crashed through the outer wall it must have broken some of our generator-connections between the two walls!"

"And the flier's falling!" I cried in turn. "It's falling toward Saturn now, with its force-rays dead—we're falling into the great rings!"

For as I glanced outward I had seen that was what was happening. The halting of the generators by the breaking of their connections between the flier's double walls had halted also the force-rays that had been pushing us out toward Neptune and that had been holding us out from Saturn's pull. With the halting of those rays the pull of the mighty planet had at once gripped our space-flier and now we were moving at swiftly-accelerating speed toward that planet's mighty bulk, toward the great rings but a million miles to our left! Were falling helplessly, faster and faster each moment, toward those mighty rings, toward their vast swarms of whirling meteors in which our space-flier and all within it could meet only an annihilating death!

CHAPTER V

At the Solar System's Edge

"Out of the flier!" Marlin cried to us. "Our one chance is to get out and repair those broken connections from the outside."

"But how——" Randall began, when the astronomer broke in on him. "The space-walkers! In them we can get outside, can try to repair those connections before we fall into the great rings!"

A moment we stared toward him in sheer surprise, and then as one we were leaping toward the four big space-walkers, suspended from the flier's wall. For though we had not dreamed, in taking them with us, of any such emergency as now confronted us, we saw that, even as Marlin had said, our one chance to escape the annihilation that soon would be ours otherwise lay in their use. Swiftly, therefore, we unhooked the great cylindrical space-walkers, neither they nor aught else in the flier having any but small weight now, that weight being the result of the pull of great Saturn, toward which we were falling. Quickly swinging open the section near the cylinder's base that was its door, therefore, I pulled myself up into the cylinder, then closed its hermetically-sealing door with the small inside lever provided for the purpose.

I was standing, therefore, in a metal cylinder seven feet in height and three in diameter, its top tapering into a rounded little dome in which were small windows from which I could look outward. My arms I had thrust into the great hollow jointed arms of metal that projected from the cylinder's sides, and had at my fingers' ends inside those arms the controls of the great pincer-hands in which those arms ended outside, and the control also of the small generator inside the cylinder whose little force-ray was shot down from the cylinder's bottom. This could be shot straight down, sending the space-walker upward by pushing against some larger body, or could be shot out obliquely sending the space-walker horizontally in any direction. Once inside the space-walker therefore, with its tiny generator throbbing and the equally small air-renovator and heater functioning, I was ready to venture out into the airless void.

Glancing out through the vision-windows I saw that Marlin and Whitely and Randall had struggled into their space-walkers also, and were signalling their readiness. We grasped therefore the tools and materials we had hastily assembled for our task, these being spare plates to repair the flier's outer wall and a small molecular-diffusion welder, and then with those in the grasp of our great pincer-hands were pulling ourselves toward the flier's screw-door. In a moment we had that open, and were crowding into the little vestibule-chamber which lay between the outer and inner doors. Closing the inner one tightly behind us, we swiftly screwed open the outer door. As it opened there was a rush of air from about us as the air of the little vestibule-chamber rushed out into the great airless void outside, and then Marlin was leading the way out of that door, out into sheer space outside our falling space-flier!

I saw Marlin drawing himself in his space-walker through the door and then floating gently out that door, floating in space a few feet from our flier and falling at the same rate as it toward mighty Saturn! In a moment more I was following him, Whitely and Randall behind me, and as I too propelled myself with a slight push through the door, my cylindrical space-walker floated outward. I found myself, therefore, cased within that space-walker's cylinder, and floating in it in the sheer empty void of interplanetary space! Beside me was the great gleaming faceted ball of our flier, falling at the same rate as ourselves toward the huge rings of mighty Saturn, to the left. Beneath and before and on all other sides of me, though, was only space, the tremendous gulf, gleaming with the great hosts of stars on all sides, with the sun's brilliant little disk shining far behind us. For the moment our position was so strange, so utterly alien and unprecedented, as we four floated there beside the falling space-flier in our four great metal cylinders, that we could only gaze about us in sheer awe and wonder. Then Marlin, with one of the great metal jointed arms of his space-walker, motioned to us and toward the flier, and we realized that we had but little time left in which to accomplish the task now before us.

For with every moment the flier and our four space-walkers were falling at greater speed toward the colossal rings of huge Saturn, to the left, and the whirling titanic meteor-swarms of those rings were growing larger and larger. But a few hours remained before, with the growing acceleration of our free-falling flier, it would be meeting its end in those clashing, crashing meteors of the great swarm, so that if we were to repair the damage to it, and get its generators functioning again before it met its doom, we must work fast. Our four space-walkers were falling toward Saturn at the same rate as the great flier beside us, so that we hung just beside that flier in space without need to use the propelling force-rays of our four cylinders. And now Marlin, grasping with his great metal-pincer hands one of the projecting joints of the flier's great faceted walls, was pulling himself around it even as he fell with it through space, was pulling himself around to its other side, where the meteor that had struck us a glancing blow had done its damage.

In a moment Whitely and Randall and I had followed, moving clumsily in our great cylinders as we fell with the flier on toward Saturn's rings, and as we reached the other side where Marlin was hovering now in his space-walker we saw that the meteor that had grazed us had demolished two of the great facets of the flier's outer wall, and had shattered and crumpled a third. Save for a slight denting, though, the inner wall seemed unharmed, a fact that alone had saved us, but the black cable-connections between the walls were broken in a half-score places, we saw. It was that severing of the connections that had halted our great generators, we knew, so now our first task was to repair those connections, and it was upon that task that we began at once to work. Surely never had men worked under stranger circumstances than those, was my thought as we began the work of re-matching the severed connections. For we four, cased in our four great cylindrical metal space-walkers, were falling through space at a tremendous and ever-increasing rate, even as we worked upon our great flier falling with us, we were falling through the mighty void toward the whirling rings of Saturn, looming immense in space beside us. It meant annihilation for us, if we could not complete our repairs in time to escape them!

And as we toiled there at the connections, it seemed to me that never could we complete them in time to escape the great rings. For not only were there a half-score breaks in the intricate cables, but each cable held within itself a dozen smaller connections or strands that in each break must be exactly rematched. And working as we were with the great pincer-claws of the space-walker our progress was terribly slow. Minutes passed into an hour and another hour, as we labored furiously there outside the flier with those connections, and by then it seemed to us that the colossal rings of Saturn, a huge whirling storm of meteors, were but a few minutes from us, so vastly did they loom before us, and so swiftly were we and our flier falling. With the energy of utter despair we labored on there at the seemingly endless task of rejoining the intricate connections, our tools and materials that we were not using at the moment being simply released by us beside us, since they fell with us and our flier at the same rate toward Saturn and thus were within our grasp, our tools floated there beside us!

Now we were approaching the last of the connections, but now too we saw that it was only a matter of minutes before our space-flier and we would be whirling into the edge of the mighty rings of Saturn, that loomed now gigantic in their spinning meteor-masses before us! Already meteors were driving about us in space more thickly, and only by a miracle had our helplessly-falling flier escaped them so far. It seemed impossible that we could complete our task before the flier and ourselves were shot into the crashing death of those colossal whirling meteor-swarms, but we were working with the mad energy of a forlorn hope, and now too Marlin was leaning toward us with his space-walker to shout something to us. For when one space-walker touched another, their two occupants could hear each other's shouts, the sound-vibrations carried through the touching metal sides. Marlin was crying to us that but minutes were left us, and was ordering Randall to return back inside the flier and stand ready there to shoot it away from the great-looming rings the instant that the connections were repaired!

In a moment Randall had obeyed, pulling himself around the falling flier to its door and inside, while Marlin and Whitely and I worked tensely upon the last of the connections, matching and joining them with the greatest speed of which we were capable. Now it seemed that greater meteors were all about us, and now the huger, denser masses of the mighty rings were towering vastly beside us, as at plummet-like speed our flier and ourselves whirled toward them and toward death! Hanging there in sheer space at the falling flier's side, working madly upon those last connections, with all about us the glittering hosts of the stars and with beside us the titanic bulk of great Saturn and its colossal rings, we seemed caught in some unreal and torturing nightmare. Then as the huge meteor-masses of the mighty rings loomed just beside us, as I reached with the pincer-hands of my space-walker toward the last of the connections, I heard from Marlin in the space-walker touching mine a hoarse cry of despair. But at that last moment my claw-hands were swiftly joining the last connection and in the next instant came the steady throbbing of the great generators inside the flier! In that instant we had grasped our tools with one metal arm and with the other each of us had gripped the edge of the flier's shattered outer wall. And then, just as the flier and ourselves seemed hurtling straight into the mighty wall of whirling meteors that was the great rings beside us, the space-flier, with us three hanging desperately to it, was hurtling away from those rings as its great force-ray shot from inside toward them, was flashing at terrific mounting speed out from them into space!

For an instant, so terrific was the accelerating speed of the flier beneath Randall's control inside, that we three, hanging to the broken outer wall in our space-walkers, seemed on the point of being torn away from our grip on it, of falling back to Saturn once more. But in a moment more, with a great distance already between the flier and the huge rings that had almost been our doom, Randall had halted it, was holding it motionless in space by means of a steady force-ray. Then we were swiftly repairing the break in its outer wall, by means of the plates and tools to which we had clung, setting those great plates in place to replace the three shattered ones, and then welding them swiftly into the flier's outer wall integrally by means of the molecular-diffusion instrument. That done, we pulled ourselves around the flier's faceted surface to its outer door, opening that door and closing it again once inside the vestibule-chamber. Then as Marlin touched a stud the vestibule-chamber was filling with air, and in another moment we were inside the flier once more, were pulling ourselves out of the great space-walkers, with Randall already out of his and at the controls.

"That was almost our trip's end!" cried Marlin as he emerged from his space-walker. "Another few minutes and we'd have been inside the rings—would have been pounded into instant annihilation by the meteors there!"

I passed a hand over my brow. "Never again do I want to find myself in a situation like that," I said. "As it was, it was the space-walkers alone that saved us."

Marlin nodded, gazing out toward great Saturn looming gigantic still to our left. "If ever we come back," he said, "if ever we try to reach Saturn and explore it as we may some day, we'll have our work cut out for us. Those mighty meteor-masses—those rings——"

"Well, at present the farther we get from Saturn the better I'll feel," Whitely told us. "And I'm glad enough that there's no other planet between us and Neptune, at least, for Uranus is far away."

Now, recovering from the first shakiness of the reaction from our awful peril, we turned with Randall to the consideration of our position. Our great ray that had shot back from the flier, and had pushed us by its force out through the solar system, had been snapped out by the halting of the generators, and we had now only the side-ray that was holding us out from Saturn. I suggested, therefore, that for the remainder of our trip out to Neptune we turn the space-flier's rear force-ray upon Saturn instead of Earth, since Earth by now had dwindled to a small bluish-white star far behind. To train our rear force-ray upon Earth and to adjust the mechanism that kept the ray trained automatically afterwards upon the object suggested, would take more time than if we were simply to push the rear force-ray against great Saturn.

Marlin approved the suggestion, so after sending the flier out farther from Saturn and ahead of it by oblique applications of the side-ray, we held it carefully in space until it was headed toward the far green spot of Neptune, and then turned on the rear force-ray with half its full power at the start. At once, with terrific acceleration, we were flashing on toward Neptune, the giant power of the ray pushing against Saturn and driving our flier ever outward. So tremendous was that acceleration, indeed, that despite the shock-absorbing apparatus of our chairs we came near to being overcome by the awful pressure upon us. Yet it was necessary that we use the highest possible speed and acceleration, now, for our former speed and acceleration had been completely lost when the halting of the generators had allowed Saturn to pull us inward. And though we were now flashing out past Saturn's orbit, with only the orbit of Uranus between us and our goal of Neptune, we had still two-thirds of our journey before us! So colossal are the distances between the great outer planets, distances beside which the gaps between Mars and Earth and Venus and Mercury seem tiny.

With the utmost acceleration of speed that we could stand, though, our space-flier was now hurtling outward, its great force-ray pushing against Saturn with more and more power and sending us flashing forward with greater and greater velocity. In the next dozen hours of our flight we had reached again to the speed of five million miles an hour that had been ours before we had met with our misadventure at Saturn. And as we hurtled on Neptune was slowly largening before our eyes, its distant, tiny little spot of calm green light becoming bigger, brighter, though very slowly. But the eyes of Marlin and Whitely and Randall and myself were always upon that green light-spot as we hurtled on, hour following hour and day following day in our eventless onward flight through the solar system's outer immensities of space. And still our speed was steadily growing until at last, by the time we approached Uranus' orbit, we were flying through the great void at the space-flier's utmost velocity, more than eight million miles an hour.

That was a speed colossal, yet so accustomed had we four become to the space-flier's tremendous velocities that it seemed not unusual to us. Flashing through the void as we were, the only objects by which one could measure speed were the planets before and behind us, and these changed in size so slowly as to make our speed seem small. The greatest change to us in the attaining of the space-flier's immense utmost speed was the change of conditions inside the flier itself. Formerly the pressure of our constant acceleration had replaced to some degree the effects of gravitation, that pressure forcing us always towards the flier's rear, as we turned more and more power into our giant pushing ray, as we shot out with greater and greater speed. But now, with our utmost speed attained and that acceleration's pressure missing, we floated inside the flier as though entirely weightless, being attracted only very slightly toward the walls by the slight gravitational attraction of the flier's mass itself. So that now the straps across chairs and bunks and the handholds here and there on the walls that we had provided proved indispensable to us, indeed.

It was upon the fifteenth day after our start from Earth, the first day of July as I noted by Earth-reckoning, that we crossed the orbit of Uranus. As we approached that orbit, only our recording distance-dials, of course, marking the fact that we were nearing the path of Uranus, I stood or rather floated with Marlin and Whitely at the flier's rear windows, gazing backward. Behind us gleamed in the star-swept heavens the planets past which we had come, and those others beyond them. Great Saturn with his vast rings that had almost been our deaths was already dwindling fast, as our flier shot out from it with its force-ray pressing with ceaseless power against it. Already the huge ringed planet was but a tiny yellow disk of light to our eyes, so far out from it we were.

To the left, too, shone the white star of giant Jupiter, small but intensely brilliant still, while farther distant and infinitely fainter was the red spark that was Mars. Our eyes shifted from these to the bluish light-point that was Earth, and then beyond it to the little disk of brilliant fire that was the sun, its light and heat reaching us now in the smallest of quantities as we fled on into the chill immensities of the outer reaches of the solar system. There close beside that fiery little sun-disk we could also make out the silvery little light-point that was Venus, and by making use of a small hand-glass could also discern closer even beside the sun the tiny point of rosy light that we knew to be Mercury, smallest and inmost of all the planets. But as we watched there, as our space-flier hurtled on at unvarying, colossal speed over the orbit of Uranus, it was toward Uranus itself we were gazing. Far back from us on the solar system's other side hung the green spot of light that was Uranus, booming onward in its vast path around the sun, but though we watched steadily through the hand-glass toward it we were unable to make out the four small moons that accompany the great green planet, which shone with a deeper green even than the greenish spot of Neptune, ahead.

"Uranus—Venus—Mercury——," said Marlin, as he gazed musingly backward. "Those three we have not passed, yet they're no greater mysteries to us than those that we have passed. But some day——"

"Some day——," I repeated, staring back, lost in thought myself, not completing, any more than Marlin, the thought that I had started to express.

Nor did I need to complete it, for as Marlin and Whitely and I stared back to where the sun's disk sent its light bravely out across the unthinkable reaches of space that separated us from it, our thoughts were all on those three planets, on Uranus and Venus and Mercury, and on those others, Mars and Jupiter and Saturn, that we had passed. What wonders, unknown to us, might not exist upon any of those worlds? But they were wonders barred to us for the time, since time was the one thing of which we had the least, in our great rush outward to the sun's outermost planet, in our desperate race outward to attempt to save our own Earth from the doom that hovered over it. For still that doom cast its shadowing wing darkly over Earth, still Whitely's instruments informed us that the giant force-ray from Neptune was stabbing back toward the sun, turning the sun ever faster at the same remorseless rate. So that it was toward Neptune, after minutes, that we turned, taking our places in our chairs beside Randall, at the controls, and gazing with him toward the planet far ahead that was our goal.

And now that we had crossed the orbit of Uranus, some two-thirds of our colossal journey's length lay behind us, and Neptune was becoming ever brighter ahead, its pale-green spot of light having become almost as brilliant to our eyes as Saturn, behind us. As we viewed it through our telescope, too, we could make out the tiny light-point of Triton, the single moon of Neptune. Somewhat larger than our own moon was Triton, we knew, and we could see through our glass what had long been known by Earth's astronomers, that this single moon of Neptune's revolved about it in a plane sharply slanted or inclined to the plane of Neptune's equator, to the general plane of the ecliptic or solar system. And close indeed seemed the light-point of this single moon to Neptune, since we knew that it was at almost the same distance from the great planet as our own moon is from Earth.

It was toward Neptune and its little moon that our eyes turned now and in the hours and days that followed, while gradually our excitement became tense as the great planet loomed ahead of us. Soon it had become a perceptible pale-green disk, widening out as we shot on and on toward it. We would reach it, we calculated, upon the twenty-first day of our journey, twenty-one days after starting from Earth. An eternity it seemed, that period of three weeks, such vast realms of space we had come through, such tremendous perils we had dared and passed. But now all those perils and worlds we had passed, Mars and the deadly asteroidal belt, great Jupiter and Saturn and the doom that had almost been ours there, all these things faded from our minds as we found ourselves with our thoughts concentrated wholly upon the far planet that from the first had been our goal, that planet which we must reach if Earth was to be saved. For ever, ever, the great force-ray of Neptune was turning the sun faster, and now less than a hundred days remained before that turning sun would be no longer able to hold together, would be dividing and releasing fiery doom upon Earth and almost all its other planets.

What was awaiting us at Neptune? That was the question that was foremost in all our minds as we shot on in those last tense days. What manner of beings there would they be who, we had assumed, were stabbing this ray of doom toward the sun? What manner of beings could they be who could exist at all, if exist they did, upon such a planet as Neptune, a planet moving about the sun at the unthinkable distance of almost three billion miles? Upon a planet that could receive but a minute fraction only of the sun's light and heat compared to that received on Earth? Upon a planet which astronomers had always believed to be of far lesser density than Earth, of a density little more than that of liquids rather than of solids. Was it possible that upon this farthest of all the sun's circling worlds there could exist life of any kind, not to speak of life intelligent enough to stab across the solar system and spin the sun itself faster to its division and its universe's doom?

Those were the questions that throbbed through our brains now as our hurtling space-flier shot on and on, Neptune growing with each hour before us. By the nineteenth day its disk had expanded to such a degree that we were able to discern upon it the cloud-belts that had already long been seen upon it by Earth's astronomers. By the twentieth those great vapor-belts were plainly perceptible, and also Triton, its moon, had become visible to our unaided eyes, revolving close about the great planet in its sharp-slanted plane, being now behind the planet but so much above it as to be completely visible to us. By the twentieth, too, the sun behind us had become hardly more than a super-brilliant star, its tiny fiery disk bathing us still with a certain amount of light, although long before this we had ceased to rely upon its heat on our flier's sunward side and had had recourse to our own heating-mechanism. By this time too, of all the planets, only Jupiter and Saturn were visible behind us; the rest were invisible to us at the colossal distances which now separated us from then.

It was not behind but ahead, though, that we were gazing, as our space-flier flashed over the last portion of its great trip, as Neptune apparently grew in size before us. Seated in my control-chair, with Whitely and Marlin and Randall in their chairs beside me, I watched the mighty planet fascinated, as we hurtled on toward it in the early hours of the twenty-first day, that day that we had calculated would bring us to our goal. And truly, now, Neptune was looming in something of its true greatness before us. Only a tiny point of light in a telescope on Earth, hardly more than that on the long days of our journey outward, we saw it now in some size and splendor, a huge cloud-belted world as large almost exactly as Uranus, outrivaled in the solar system only by it and by the two giants of Jupiter and Saturn. Over sixty times larger than our own Earth it was, a huge world spinning far out here at the solar system's very edge, the last outpost of that solar system with beyond it only the awful emptiness of interstellar space.

Silently we gazed toward its great, green disk, its small gleaming moon, as our space-flier throbbed on toward it. Whitely, as usual, was checking from time to time the performance of the never-ceasing generators whose great force-ray, pressing against Saturn still, was hurling us forward. Randall was gazing forward with me, helping me now and then to ascertain from our speed and distance dials our distance from the great planet. Marlin had applied himself to the telescope, was gazing ahead through it toward the big world's cloud-wreathed surface, touching a focusing wheel now and then. For minutes we throbbed on thus, the beat of the generators the only sound in the hurtling space-flier's interior, but at last Marlin drew back from the telescope's eye-piece and frowned as he gazed toward the great green planet ahead.

"I can make out nothing through those cloud-belts," he said. "Those belts show, as astronomers have always believed, that Neptune has a great atmosphere. But what lies beneath them we'll not know until we penetrate through them to the planet's surface."

"That won't be long," I told him. "We're already only fifty million miles from Neptune—should reach it in seven or eight hours more."

"You'll be slowing the flier's speed before long then?" asked Whitely, and I nodded.

"We'll wait until we're ten million miles from it and then cut out our rear-ray that's pushing us on, and send out a front force-ray toward Neptune to break our progress."

Those next several hours, however, seemed to us in passing to be drawn out to infinite length, so great had become our suspense. At last, however, as we stared tensely ahead, Randall gave the word beside me that marked our place as within ten million miles of the great planet, which had now grown to a vast pale-green cloudy disk in the heavens before us. And as he gave that word I snapped shut one of the six switches before me, turning off the great rear force-ray of the flier, and at the same moment snapped open another switch that sent a great force-ray stabbing straight out from the ray-opening in the flier's front, stabbing straight out toward the great disk of Neptune ahead!

Almost at once our mad flight toward that huge world began to diminish in speed. Minute by minute the figures on the speed-dial crept backward, so that from eight million miles an hour our speed dropped quickly to six million, and then to four and to three and to two million.

With this swift decreasing of our speed we were experiencing now the reverse of that pressure that had been ours upon our acceleration, since now we were straining upward and forward against the straps of our chairs, the pneumatic shock-absorbing apparatus of those chairs functioning now as it had done then. But though we felt again the dizziness and slight nausea attendant upon these tremendous changes of speed, we forgot that in our intent contemplation of the huge world that loomed but a million miles ahead, its tremendous pale-green sphere, belted with great cloud-masses, seeming to fill the heavens before us. Already Marlin, with his instruments, had found as we neared Neptune that the giant world's rotatory speed was a little more than twenty Earth-hours, solving a problem that long had defied Earth's astronomers by the discovery that the great planet turned on its axis each score of hours.

An involuntary thrill of pride ran through me even as we shot in toward those great cloud-masses that encircled Neptune. Neptune! The sun's farthest world, and we four had reached it, had shot across the awful gulf that none had ever thought to span! Marlin, beside me, was gazing forward into the great cloud-layers now with the astronomical curiosity of all his career gleaming in his gray eyes, as we approached this farthest of our solar system's worlds. Whitely was contemplating it with his usual cool detachment, but thoughtfully. Randall's face was as eager with interest as my own must have been, and when, a little later, there came a low mounting roar of sound around our flashing space-flier, the roar of an atmosphere through which we were rushing, he uttered a low exclamation, swiftly manipulated our outside air-tester, and then turned to us.

"An atmosphere to Neptune, surely enough!" he exclaimed. "About twice the pressure of Earth's, even this far out, and the air-tester shows a large percentage of water-vapor and rather larger amount of oxygen. Otherwise it seems much the same as Earth's."

Marlin nodded. "We should be able to move in that," he said, "but the greater gravitation of Neptune will probably be such as to make it necessary to keep inside the space-walkers."

But now the space-flier was hurtling into the outer vapor-layers, that swirled about us in white mist-masses in the pale light that came to us from the tiny, distant sun. Onward and downward through those vapor-layers, through the cloud-belts about the great planet, our space-flier shot, while we four gazed ahead and downward, now with excitement keyed to an utter tenseness. Then with sudden stunning surprise, for we had thought those cloud-layers of immense thickness, our space-flier shot out and down from them, shot down into clear air, clear atmosphere. And as it did so, from the four of us came simultaneous cries. For there in the pale, dim unEarthly light there stretched far away beneath us the surface of the planet that for so long had been our goal on our great race to save Earth from doom, the surface of great Neptune!

CHAPTER VI

Into Neptune's Mysteries

"Metal, over all Neptune's surface!"

"A metal-covered world!"

Our stunned, astounded exclamation sounded together there as we gazed downward from our flier, whose drop I had instinctively halted. For it was metal indeed that lay beneath us, a gigantic surface of smooth dark metal or metallic substance that glinted dully in the pale light that fell on it, and that stretched away in all directions to the horizons, completely covering the giant planet Neptune as far as we could see! A metal-covered world! In amazement, in awe, we stared down upon it in that moment. For we had expected many things, many aspects which the surface of Neptune might have had, frozen ice-fields or flaming craters or even a liquid world, but never had we expected what we now saw beneath us. Never had we expected to find the huge planet thus sheathed in a dark metal covering that apparently extended over all its gigantic surface! And in all its vast smooth expanse, we saw, there was no higher structure of any sort, nothing but the level plain of smooth dark metal, sweeping far away to the flat horizons.

"Neptune a metal-covered world! And I think I see why, now," said Marlin quickly as we gazed down. "I think that I can understand why the beings of Neptune have covered their world with this shield——"

"But what lies beneath it?" Randall asked. "Do you mean that these beings of Neptune——"

"I mean that beneath this great shield they have built must lie the real world of the beings of Neptune—must lie the source of the giant force-ray that they're stabbing toward the sun!"

"But how to get down inside?" said Whitely. "There seems no opening in this gigantic metal shield——"

"We must go on, then," Marlin told us. "Must go on until we find some way of getting beneath, since beneath that shield there lies our goal!"

A moment we stared toward each other, and then I had snapped open one of the switches before me, turning the ray-direction dial, sending down slantwise toward the metal surface a force-ray, instead of the vertical ray that had upheld our flier. The pressure of this slanting ray at once sent our ball-like space-flier moving forward across Neptune's surface, across the smooth vast dark metal plain whose presence was so astounding to us. I glanced at the outside-temperature dial as we shot forward, saw that the atmosphere through which we moved though dense was cold indeed, hardly above zero in temperature. Then with Marlin and Whitely and Randall I turned my attention to the smooth great metal surface over which we were driving. On and on we shot, though, without finding any slightest change or opening or structure in that unending dark metal surface, that swept away in its vast, bare curve to the horizons, which were very far from us, so great was the radius of curvature of Neptune's mighty sphere. But after tense moments of this fruitless watch from our racing flier, Whitely uttered a low exclamation and pointed ahead, toward a round lighter circle in the dark metal plain far to the left, a circular opening in the giant metal shield!

None other of us spoke as we gazed toward that opening, but at once I had sent the space-flier rushing toward it. As we raced nearer to it we saw that that opening's circle was a full five hundred feet in diameter, and that we could see down through it a great, bright-lit space beneath! Tensely we watched, until in another moment I had sent the space-flier directly above the great opening, so that it hovered motionless above the circular opening's center. And as it hung there we four, forgetful for the moment of all else, were gazing down through the space-flier's window through that opening, down into the great more brightly-lit space that we could see beneath, beneath the huge metal shield that covered all this world!

The first thing that I noted, gazing downward, was that the space beneath the giant metal roof of Neptune was a great one, since it was a full mile from the opening in that roof to the surface of the world far below. Gazing down toward that surface, seeing at last the true surface of Neptune lying in the brighter light that existed in some strange way beneath the gigantic metal roof, we gasped. For upon that surface there loomed countless strange structures such as we had never seen before. Rectangular in shape were those structures, with straight black walls, of great size but seeming rather low in height, and they were without exception roofless! In them we could dimly make out from our great height the gleaming shapes of what seemed huge machines of one sort or another, but could not at that height see whether living beings of any sort moved among the structures. The great circle of the world beneath that we could see, hanging above the opening, was completely covered with these structures, the black walls of one roofless building being surrounded on all sides by the walls of others, there being no streets or open spaces whatever between them! It was as though, indeed, all the surface of the great world beneath had been divided into great compartments by a great checkerboard arrangement of intersecting black walls!

Marlin's eyes were gleaming with excitement as he gazed down. "The city of the creatures of Neptune!" he breathed, as in awe we four stared down. "The city of Neptune that lies beneath the colossal roof, and that must hold somewhere that which we have come to seek!"

"You're going to venture down into this city—down under the great roof?" I asked, and he nodded.

"We must, Hunt, to find the giant force-ray's source. But stand ready to flash the space-flier back upward—for if we're discovered by whatever beings inhabit this strange world, I think we'll get short shrift!"

A moment we paused there, and then as my hands moved upon the switch-controls, decreasing the power of the force-ray that held us upward the space-flier was sinking smoothly and slowly downward, down through the great opening! Tensely and with fascinated interest we gazed about now as we sank into the great space that lay beneath the huge metal roof. That space was brighter-lit than above the roof, we saw, and as we turned a moment to glance upward we saw that looking upwards, the roof was perfectly transparent! Dark, opaque metal when seen from above, it was almost invisible in its transparency when seen from below! And, seeing that, we understood the great roof's purpose. It had been constructed and placed above all Neptune, encircling the great planet and enclosing it, to retain that planet's heat as much as possible. For it was apparent that heat and light radiations or vibrations could not pass up through the metal of the roof from beneath, making it appear black and perfectly opaque from above, but could pass freely down through it from above, making it appear almost perfectly transparent from below!

Even as we grasped the wonder of that, though, we had forgotten it, in the greater wonder of the things that lay now before our eyes. For as we sank down in our space-flier into the great space beneath that roof we could see the surface of great Neptune itself, stretching far away beneath that mighty enclosing shield above it, and covered to the horizons by the strange rectangular and roofless structures such as we had already seen. These were formed, indeed, by smooth black walls of some two hundred feet in height that ran in straight lines in checkerboard arrangement across all the surface of this huge planet, apparently, forming upon all its surface, without streets or parks or openings of any kind, a vast city of rectangular compartments, large and small! A titanic streetless city that covered apparently all the surface of giant Neptune!

But most wonderful of all the things that lay before us in that moment was the fact that nowhere about us could we see any sign of supporting pillars or piers for the giant roof that stretched far above us! For though we could gaze far away to the distant horizons of this great world, we could find no single support for that huge metal roof that apparently covered all the great planet, and whose weight must have been incalculable! And another feature of the giant roof puzzled us. It puzzled us to see the great openings in it like that down which we had come, great circular openings which we could see in it here and there at great distances from each other. Those openings were provided on their under-side with great sliding shutters for closing them tightly, yet all were open! Why should they be open, we silently asked ourselves, if the purpose of the roof was to retain Neptune's heat within that roof? For the existence of those great and unclosed openings in the roof must surely be defeating that purpose, for our outside-temperature dial recorded the same zero temperature as prevailed above the roof!

Yet even these strange things could not wholly draw our interest and attention from the strange compartment-city beneath, as our space-flier sank toward it. We were within a few hundred feet of it, now, and as we dropped nearer, Marlin and Whitely and Randall staring eagerly down beside me, my hands were tense upon the switch-controls, ready to send our flier leaping instantly upward. For if the beings of the city beneath, whatever their nature, caught sight of us, we could expect nothing but instant attack. So that a tenseness held all of us as our great flier's faceted polyhedron dropped on through the pale light beneath the great roof toward the black-walled, checkerboard-like city that stretched across the surface of the great world beneath us. And now, as we sank lower, our eyes were making out ever more clearly the details of that amazing city.

The rectangular black-walled compartments held, as we had half-realized from above, various strange-shaped mechanisms and objects which we could even now only vaguely discern. We could see clearly, though, that here and there across all the vast city's compartmented surface there stood giant metal globes, each a hundred feet in diameter and each occupying a square compartment of its own. There seemed hundreds of these great gleaming globes, scattered here and there in compartments across the city's surface as far as we could see, though their purpose was then quite incomprehensible to us. But as we sank lower still, ever more cautiously, it was not the globes or the compartments' contents that held our attention so much as the astounding, stupefying fact that now was thrust upon us—namely that in all the gigantic compartmented city, in all its strange great black-walled rectangular and roofless enclosures, there moved no living being!

"Dead!" Randall's cry expressed in that instant the stupefaction of all of us. "A dead world!"

"Neptune—a dead world!"

A dead world! For truly it seemed a dead world that lay there in the dim pale light beneath us! A world whose strange contiguous compartments stretched away from horizon to horizon to form the colossal city above which we hovered, but a world, a city, in which was no single discernible thing of life! The endless black-walled compartments, the strange-shaped structures and mechanisms, the great enigmatic globes—all these things lay beneath us in a silence and a death that were stunning to our senses! Lay beneath us as though death had reached out of the unknown to annihilate suddenly all living things upon this alien world, leaving in it only the cold and the silence and the death that enwrapped it now! Neptune—we had flown across the awful void toward it for week upon week, prepared to find within it any strange beings, any alien and terrible form of life, but never had we been prepared to find it without any life whatever—an utterly lifeless world!

As we stared down toward it in utter silence it seemed to me that my brain was spinning from the stupefying shock of amazement that was ours. For if the world beneath us was truly a dead one, if Neptune lay now without life, its colossal compartment-city entirely lifeless, whence came that giant force-ray that was stabbing across the solar system from Neptune to turn the sun ever faster toward its division? Whence came that doom which was being loosed upon our Earth and upon all the solar system, almost, by that gigantic ray? Was that great ray, after all, only some incomprehensible freak of natural forces, impossible to withstand, and had Neptune, once the home of some alien, mighty civilization, lain for eons in silence and death? Had our desperate mission which alone held a chance for Earth, our terrific race out through the unthinkable reaches of the solar system's spaces toward its outermost planet, been in vain?

Marlin must have felt something of the same despair in that moment, but his strong face betrayed no trace of it as he turned to us. "It's evident that this vast compartment-city, this whole world, perhaps, is deserted," he said. "But where does the great ray come from?"

Whitely shook his head, glancing at his instruments. "Impossible to say," he said. "The recording-instruments here show only that we are close to the great ray's source, that that source is in the region around Neptune. But the emanations or reflections from it striking the instruments are so powerful as to make it impossible to determine the ray's source exactly."

"But the city beneath!" I cried. "Even if it is dead, deserted, we might be able to find in it some clue to what has happened here, some idea of what manner of creatures the Neptunians were, and perhaps some clue to the great ray's source!"

Marlin pondered, then nodded. "Hunt's right," he said. "If we explore this deserted compartment-city beneath we may find some suggestion that will lead us to the great ray's source. And we must find out soon, for only eighty-five days are left before the sun divides into a double star and dooms Earth!"

"But we shouldn't risk all of us on this venture," I said. "The safest way would be to keep the space-flier, with two of us inside, hovering here above the city while the other two go down to it and explore it in their space-walkers."

This we finally agreed to do, and Marlin and I insisted upon being the two to make the venture, Whitely and Randall reluctantly agreeing at last to remain within the space-flier, watching and waiting for us. So, bringing the space-flier down to a height of a thousand feet above the compartmented city, I set the force-ray to hold it motionless there, Randall taking my place at its controls. Then Marlin and I were quickly getting into our two cylindrical space-walkers. Once inside them, we each gripped in a great pincer-hand the pointed bars of steel that we were to take with us, and then unscrewed the inner door and passed into the vestibule-chamber. Another moment and with the inner door closed, the outer one was swinging open, and the denser and colder air from without was rushing into the vestibule-chamber. We did not feel its cold, however, snug in the insulated and heated cylinders of the space-walkers, but drew ourselves to the outer door, turning on the force-rays from the bottoms of our cylinders. Then as we drew ourselves out through the door and into empty air, we were both sinking gently downward, our fall slowed to a mere floating drop by the down-pressing power of our force-rays.

Down through the dim pale light of Neptune's day we sank, down until just beneath us lay one of the intersecting black walls. As I saw this I shot my supporting force-ray outward at a slant, and as this sent me down obliquely, I floated down past that wall, Marlin doing the same beside me, and in another moment we had come gently to rest just above the black smooth floor of one of the great compartments, the force-rays from the bottoms of our space-walkers holding us a foot or so above the floor. Resting there, Marlin and I looked up first. Beside us towered the black two-hundred foot wall of the compartment, and far above we could make out the hovering space-flier, its great gleaming polyhedron hanging motionless and watchful above. We waved the great metal arms of our space-walkers toward it, toward Whitely and Randall inside it, and then turned to examine the place in which we stood.

It was an oblong compartment some four hundred feet in length, and half that in width, its great black walls towering on all sides of us. Ranged around the compartment against those walls were rows of strange squat mechanisms of a roughly pear-like form, that loomed each a score of feet in height. Marlin and I shot our space-walkers toward the nearest of these mechanisms, to examine it. We saw that in the top of it was an odd cone-like opening, and that there ran out of the gleaming metal cover of the thing a thick pipe or tube that connected with a larger pipe that encircled the compartment, connected to each of the mechanisms. Then as we reached forward, swung aside the metal cover of the mechanism, exposing an intricate system of sections inside it through which ran slender tubes acted upon by what seemed projectors of electro-magnetic force about them, Marlin pointed toward them, leaned toward me until his space-walker touched mine and spoke to me through the touching metal.

"A water-making mechanism this seems to be, Hunt," he said. "In some way it must draw down ceaseless supplies of hydrogen and oxygen atoms from the great vapor-masses above the roof, and then recombine them here into water."

I nodded, gazing at the thing. "But it hasn't been used for years—for centuries, perhaps," I said. "Look—that dust upon it——"

For upon the pear-shaped mechanism before us, and on all those others and all other things about us, there rested a coating of fine dust that was inches thick, a dust-coating that we knew only a great period of time could have deposited there. A moment we stared at that, two grotesque figures there in the great cylinders of our space-walkers, and then were moving on, along the wall. That black smooth wall, we saw now, was composed of a material that looked much like a black seamless stone, but one that seemed diamond-hard. For our pointed steel bars could make not the slightest impression upon it, and it was evident, from the monolithic construction of the great walls about us and of the smooth black paving upon which we walked, that this diamond-like smooth stone had been artificially made. Later we were to learn that it was constructed by a building up of molecules into a deliberate crystalline formation that far exceeded the strength and stability of any other material's crystalline structure, and thus gave to the black artificial stone a diamond-like hardness and a tensile strength exceeding that of steel.

Around the great compartment we walked, our eyes ranging over the great pear-shaped mechanisms and the great pipes connecting them, and then Marlin and I stopped short. For there in the black wall before us was a door, an opening that connected with the adjoining compartment on that side. It was by means of doors like that, it was plain, that the necessity of streets in this compartment-city had been obviated, making it possible to pass across the city through the compartments themselves if needed. Yet it was in stupefying surprise that Marlin and I now gazed toward that door. For it was all of six feet in width, but hardly more than four feet in height! Its opening stretched there in the black wall as though an ordinary door-opening of one of Earth's buildings had been set in that wall sidewise! And as we looked stunnedly about we saw that all the doors set in the compartment's four walls were of the same size and shape!

"Those doors!" I cried to Marlin, leaning beside me. "Those were never made for human beings or for near-human beings!"

"Then these Neptunians that once were here—" Marlin began, and then stopped; we gazed in silence at each other through the vision-windows of our space-walkers.

And silence seemed oppressive all about us then, a silence that lay as thickly over the deserted compartment-city as the thick dust of unguessable years that covered it. A chill seemed to have struck home to us in some strange fashion with the discovery of those grotesque door-openings and their significance. I glanced upward, saw that the faceted ball of the space-flier was still hanging motionless high above, and then as I turned back saw that Marlin had moved toward the low door toward which we had been gazing. A moment he contemplated it, then motioned to me with the big metal arm of his space-walker, and as I came to his side, grasped that door's edge with his great arms and lowered his space-walker's big cylinder until it lay on its side on the smooth black paving. Then he was drawing it through the door, aiding himself with a force-ray shot from the opening in its bottom toward the compartment's opposite wall behind us. When he was through, he drew himself erect, and in a moment I had followed him and was standing with him in the next compartment.

That second compartment, we found, was a replica of the first, being of the same size and holding within it several dozen more of the pear-shaped water-manufacturing mechanisms. We passed through it, therefore, over the dust-strewn paving and through the low similar door on its opposite side, to find ourselves in still another compartment of water-manufacturers. Pressing on, rapidly becoming able to pass through the low strange doors easily in our cumbrous space-walkers, we passed through a half-score more of similar compartments all holding only the dust-covered, pear-shaped water-mechanisms, and then at last we passed into a different compartment, one that held a strange shelving that covered all its walls, at which we stared in perplexity for some time.

This shelving consisted of horizontal and perpendicular shelves of smooth black stone like that of the walls themselves, running along and up and down those walls and forming thus a continuous series of box-like openings, each some four feet in length and two in height. There were hundreds of these shelves in the compartment, we could see, yet all of them were quite empty, and in the compartment there seemed to be no other object. They suggested the equipment of a store-room, yet there was no faintest clue as to what had been stored in those shelf-tiers of openings, ranged one above the other all around the walls. Had Marlin and I been able to guess the astounding truth as to those tiers of compartments as to their significance and purpose, much would have been clear to us right then. As it was, after vainly endeavoring to fathom the purpose of the things, we gave it up and moved on out of the compartment, and through similar shelf-tiered compartments beyond it.

By this time we had passed some distance from beneath our hovering space-flier, but still could see its gleaming polyhedron hanging high in the air behind us. Reassured by the sight of it, we passed on, and in the next half-hour progressed through many more compartments. Some of these contained water-manufacturing mechanisms or tiers of strange shelf-openings such as we had already seen. But many others held mechanisms or objects strange to our eyes, before which Marlin and I stood entranced. We almost forgot, in the overpowering interest of the things that we found in those compartments, the object of our exploring search through the strange compartment-city, our search for clues as to the beings of Neptune and as to the great force-ray that was turning the sun ever faster.

Compartments we found in which were structures that puzzled us as completely as had the tiers of shelf-openings. These structures were great flat metal containers, each scores of feet in length and width but hardly more than a foot or two in depth. They were ranged one above the other in great supporting frameworks, and each container was filled with black fine soil. The compartments that held these had set in their walls great white disks which were connected to intricate apparatus that seemed generators of some kind of force, but more than that we could not ascertain from our inspection of them. The whole arrangement, the great shallow containers of soil, the disks in the walls, the generators connected to them—all was utterly enigmatic and perplexing to us, and we were forced to give up the riddles and pass on into other compartments, in which were other things almost as mysterious.

Some held giant globes of burnished metal, now dust-covered, which occupied almost a whole compartment each. These great gleaming globes were among the most puzzling things we had found, since there was, in the compartment of each one, no other object or indication of their purpose, save for a few switches mounted upon a panel, the combination of which we could not discover, opening and closing them in vain. We had seen these great globes from above, dotting the vast compartment-city here and there in great numbers, but we could learn no more of their purpose standing there beside them than we had been able to guess from above. And near these there were strange looming machines, many-cogged and with a great hopper above whose purpose we guessed, at least, guessing that these were the mechanisms that produced from some raw materials the artificial diamond-hard black stone-material that made up all the intersecting walls of this strange huge city-world.

Each of these machines had before it a very low, round metal seat, with in front of that seat the controls of the machine, a half-dozen burnished metal levers. As we saw them Marlin and I exchanged startled glances. Had the being who operated that machine, who sat before it, held and operated all those control-levers of the mechanism? Back to our minds flashed the strange low openings of the doors through which we had come, and for a moment the same strange sense of dread chilled me. But I shook off the feeling, followed Marlin on into another compartment, glancing back through to where our space-flier poised in the air now far across the city behind us.

It was into another long rectangular compartment that we passed, one that held, like that out of which we had just come, rows of strange many-cogged mechanisms. But one feature of that compartment caught our attention instantly, held us motionless and staring. And that was that those rows of great mechanisms were not complete! Here and there in those rows were gaps, as though machines had been removed from the compartment, and where those gaps were, where the missing machines had stood, were squares on the floor where their bases had rested, squares that were entirely free of the inch-thick dust that lay over all else! And even as we stared, as we comprehended the astounding significance of that, we saw that upon the dust-coated floor before us were many tracks, small round and strange tracks in the thick dust that were of great number and that had been made, it was apparent from their dust-free condition, but days or hours before!

"Marlin!" I whispered, grasping my companion's space-walker with the great metal arm of my own and touching head casing to head casing. "Marlin—those tracks—someone, something has been here—and but recently!"

"It can't be!" he exclaimed, his voice hushed strangely like my own. "Neptune—all this great compartment-city—it's all dead, deserted——"

"But those tracks!" I insisted. "Those squares in the dust—something's been here and has taken a half-dozen of these great machines away with them! And we know that something on Neptune is sending the great force-ray out to the sun!"

"It can't be," Marlin repeated. "We found no source of the great ray on Neptune's sunward side, and, too, how can that ray shoot always toward the sun from some spot on Neptune when Neptune itself is constantly turning? No, Hunt, I think that this means—but look up there!"

As he cried out he was gazing suddenly upward, his space-walker's great arms pointing up, and at that horror-stricken cry, I glanced up to see a sight that froze me motionless there in astonishment. For there, high above us and above the great compartment-city, a dozen strange great shapes were dropping down through the air toward us, were dropping down through one of the openings in the great roof! Long great cylinders of gleaming metal those shapes seemed, dropping silently and smoothly down from the opening, toward the compartment-city, but even as we looked in amazement and terror up toward them, they had halted in mid-air, as though seeing the faceted ball of our hovering space-flier hanging above the city far behind us. Then the next instant all the dozen great cylinders were flashing with unbelievable speed toward our space-flier, a half-score narrow, pencil-like rays of pale, almost invisible light or force stabbing ahead of them toward the space-flier!

Marlin and I cried out in the same instant as those great cylinders whirled through the air toward the space-flier, and in that moment it seemed to us that our wild cries had been heard, for we saw the space-flier whirl itself to one side suddenly, as though Randall and Whitely in it had caught sight suddenly of that onrushing menace. The pale, almost unseen stabbing little rays of force or light shot past them as they swerved thus, and then the next moment cylinders and space-flier seemed to be whirling in a wild melange of geometrical metal forms there in the pale dim light above the great compartment-city. We saw the slender, pencil-like shafts of force stabbing this way and that, saw one cylinder, struck by the shafts of its fellows, riven asunder by those shafts as though by swords of steel and then suddenly the gleaming polyhedron of the space-flier had plunged up out of the wild mêlée and was rocketing up toward one of the great openings in the vast roof above!

As Whitely and Randall thus whirled the space-flier up in an effort to escape their outnumbering, unknown attackers, we saw three of the great cylinders rushing up after them. In another moment the space-flier, closely followed by its three pursuers, had rushed up through the opening and disappeared above, and as they did so we saw that the remaining eight cylinders were dropping now again toward the compartment-city! Watching stupefied still in our amazement, Marlin and I saw that four of the cylinders were heading down toward a point in the great city somewhat to the right of us, while the other four were slanting down now almost straight toward the compartment in which we stood! And as I saw that, as I saw and understood the significance of the tracks and missing mechanisms in this compartment, I grasped Marlin's great metal arm with one of my own, again touching head-armors.

"They're coming down to this compartment!" I cried. "It was they who took the missing mechanisms from here—they've come for more!"

"Out of the compartment, then!" Marlin shouted. "They're after Whitely and Randall in the flier, and if they find us here——!"

With the words we were throwing ourselves, prisoned in our great cumbrous space-walkers as we were, toward the low door through which we had come. In a moment we were through that door, were in the adjoining compartment, but hardly had we gained it than there swept through the pale light from high above four great cylindrical shapes, slanting smoothly down toward the compartment we had just left! From above they could see us easily, whatever beings were inside those descending cylinders, so that as they shot down over our roofless great compartment, Marlin and I poised motionless, praying that our great gleaming space-walkers might be mistaken for mechanisms. Far across the compartment-city we could glimpse the four other cylinders dropping down toward a different point, also, and then in the next moment the four above us had shot down over us and with a throbbing sound coming clearly to us from those cylinders' interiors, were coming to rest in the compartment we had just left!

Glancing for a moment at each other through the vision-windows of our space-walkers, Marlin and I then softly moved in them toward the low door through which we had just come. For though our fear was great, our curiosity, our realization of the mission that had brought us out here to Neptune, was greater. In a moment we were at the door, were lowering ourselves awkwardly and silently to a position from which we could gaze through it into the adjoining compartment. In that compartment, we saw now, the four great cylinders had landed, and were resting upon the floor at its center. Each cylinder was of forty feet diameter and twice that in height, and their gleaming metal sides were broken here and there by small windows. They were broken too, we saw with a start, by ray-openings like those of our own space-flier, and it was evident from those that the cylinders were propelled through space by the same force-rays that moved our flier!

Before we could fully comprehend the meaning of that fact, though, there came a low clanking of metal and before our eyes a section in each of the curving sides of the cylinders, near the base of each, was abruptly sliding aside, leaving in the metal wall of each cylinder a low oblong door-opening like those of the compartments about us. Now we heard from inside that opening a stir of movement, and saw vaguely a shape or shapes that moved in the cylinder's dark interior. Then, as we gazed with tense nerves toward that opening, there moved out of the cylinder's dark interior through that opening, into the pale dim light of the Neptunian day, a creature at which Marlin and I stared in that moment with horror-stunned minds! A being so grotesque and so awful in appearance that for the moment it seemed to me that it needs must be a creation only of our over-strained nerves and brains!

It was a creature that bore no conceivable resemblance to the human form or to any other in our knowledge. The body was a great flat disk of pale-green flesh, five feet in diameter and hardly a foot in thickness. It was supported in a flat or horizontal position above the ground by seven short thick limbs of muscle or flesh, which were each three feet in length and which projected down from the big disk-body at equal intervals around its circle. The only visible features of the creature were the eyes and mouth. The eyes were two in number, and were set close together in the edge of the disk-body. They were like the eyes of some insect, being each inches across and bulging outward, being composed each of a myriad smaller glistening lens-divisions, like the eye of a fly! And as I saw with shuddering horror those two bulging strange eyes gazing about, it came to me that it was only by means of such great, powerful eyes and their many lenses that any creature here in the dim light of Neptune could see clearly all things about it!

The mouth was a white-lipped circular opening, and was set at the very center of the horizontal disk-body's upper surface! No stranger combination can be imagined than that which presented itself thus in the appearance of that creature before us, with the two bulging glassy eyes staring forth from the edge of the great disk-body, and the round mouth gaping there in that disk-body's flat upper surface. Slung around the disk-body the creature wore a flexible armor or dress of connected straps of flexible metal. In a loop of this rested a metal tube formed by the joining together of two tubes of dissimilar thickness. And attached to the flexible straps in another position, at the disk-body's edge, was one of the strangest features of its appearance, a small metal ball that seemed glowing with unceasing radiant light!

The creature gazed about him, unaware of our awe-stricken gaze, and then half-turned and seemed to call to others in the cylinder from which he had emerged, a strange sound issuing from his mouth-opening. That sound was like a swift succession of staccato snaps of sound, as clear and sharp as the snap of metal on metal. From the variation in their utterance, though they were in a single pitch only, it was evident that they formed the speech of the strange creature, and as he gave utterance to them, others like him, other similar disk-bodied green beings, were emerging from the cylinder behind him and from the other cylinders. In a moment a score or more were gathered there, moving toward the great cogged mechanisms beside them, and as they did so the staccato snapping of their strange speech came loud to our ears. And as they did so, too, we saw that the seven strange limbs of each of them served him as arms as well as supporting legs, since some used some of those limbs to carry tools, holding them tightly in fingerless, muscled grasp!

"Neptunians!" whispered Marlin beside me. "Neptunians, Hunt—those squat, flat disk-bodies—those great eyes——!"

Neptunians! Yet I had seen myself that they must be so, that only on a great planet like Neptune, with far greater gravitational power than Earth, could those squat, flat bodies have evolved. For the greater the power of a planet's gravitation, the lower and the more squat will be the forms of life that evolve upon it. And just as these Neptunians had evolved in their strange disk-form here on the great planet, due to its greater gravitational power, so had their great light-gathering eyes been evolved by the dimness that reigned here always. And it was these beings, it was clear, who had built the vast compartment-city that covered all of the great planet's surface about us, since it was only beings like these who would have built such strange, low doors in it for their own flat disk-bodies, only such beings as these who, with their seven great limbs, could manipulate the controls of the mechanisms we had seen!

"Neptunians!" I whispered it, myself. "But if it's beings like these who inhabit Neptune, who have sent the great force-ray stabbing toward the sun to divide it, where are they all? Why have they left all this city, all this world, dead and deserted?"

Marlin, inside his space-walker, shook his head. "God knows, Hunt! If all these Neptunians have deserted their world, where have they gone? I know no more than you. But it's clear that they've come back for more of those great mechanisms."

It was, indeed, evident that that was the object of the Neptunians' visit to the compartment-city, for now the score or more in the adjoining compartment were busily working with their tools upon three or four of the great cogged mechanisms that loomed there. Swiftly they were taking down those mechanisms, were dissembling them into a myriad intricate parts which were stowed away in the four great cylinders. More than once some of them passed close to the low door through which Marlin and I were gazing, but none ventured through it into the compartment in which we hid, seeming all to be intent upon the business at hand. And as they worked on we began to understand some of the features about them that had puzzled us in our first horror-stricken sight of them.

We had been puzzled, indeed, that they were able thus to move about unheedingly without protection of any sort in the zero-cold that reigned about us. But now as one or two of them passed close to the door by which we crouched, I gazed closely at the glowing little ball that each had attached to his metal armor, and guessed then what I was later to learn was the truth, that that ball was glowing with radiant heat and had the power of heating to comfortable temperature the atmosphere for a few feet directly around its wearer. Thus the wearer of it moved always in a little volume of warm air, though the air outside that area might be at zero temperature. And thus it was that the Neptunians were able to withstand the bitter cold about us, from which we were protected by our space-walkers.

As we gazed toward the Neptunians, they were completing the process of dissembling and stowing away the great mechanisms, and now I moved closer to Marlin, my thoughts being on retreat from the dangerous position in which we were. Not only might we be discovered at any moment by the Neptunians before us, but somewhere in the compartment-city behind us were others, we knew, who had landed in their four cylinders at another point. Whatever had happened to Whitely and Randall in the space-flier, Marlin and myself were in the most perilous of positions. Even were we to escape the Neptunians we could not exist for long in our space-walkers in this dead and deserted city, in the cold of this strange and terrible world of death. Yet to escape from them was our first consideration, and I whispered as much to Marlin through our touching space-walkers.

"We've got to get clear of these Neptunians," I whispered to him. "Back farther in the city we can hide until they go."

He was gazing toward the strange creatures and their tools and mechanisms with intense scientific interest, but turned toward me at my whisper. "We'll get back, then," he whispered. "It may be that Whitely and Randall——"

It was a sentence that he never finished. For we had hardly turned to cross the compartment in which we crouched than we had to stop short in our space-walkers. There behind us a dozen or more great disk-creatures had been standing—a dozen or more great Neptunians! Even as we faced them there in that stunned moment, their bulging glassy eyes upon us, I saw the tracks in the thick dust at our feet, realized that these creatures were of the others who had landed in the compartment-city, and that finding our space-walkers' tracks here and there in the thick dust, they had followed them, had trailed us and stolen behind us while we watched their fellows! Then in the next moment had come a staccato cry from the foremost of the Neptunians, and in the instant following they had flung themselves straight forward upon us!

For in this atmosphere sound penetrated our cylinders.

CHAPTER VII

The Giant Ray

The minute that followed was a grotesque whirl of swift action, a desperate reeling struggle between Marlin and me cased in our great space-walkers, and the great disk-bodied Neptunians. Even as they had leaped upon us, we had shot to one side, had brought down upon the foremost of them the great steel bars carried in our pincer-like metal hands, and had sent two of them crumpling to the black paving with a thick green liquid oozing from their shattered bodies. The remainder, though, were upon us before we could strike again, and then as they gripped us I could see the Neptunians who had been working in the adjoining compartment come running toward the combat, to assist their fellows. So that though Marlin and I struck out with desperate fury at the monstrous creatures with the great metal jointed arms of our space-walkers, they had in a moment more with their numberless limbs fettered our arms and torn the bars from our grasp, holding us then motionless and helpless.

Thus held, part of the creatures stepped back from us, and then we heard one of them, who bore a single, crimson-circle device upon his metal dress or armor, utter a staccato order to the others. At once four of them drew from their armor the long tubes we had noted there, and trained them upon us. I knew, instinctively, that those tubes held some deadly force like that with which the cylinders had attacked our space-flier in the battle in mid-air. Later I was to learn that the tubes could release a force-ray similar to that used for propulsion by our space-flier and by the cylinders—a force-ray so concentrated into a pencil-like beam that, instead of merely pressing against whatever it struck, it pierced whatever it touched with terrific force, riving it asunder. Knowing the deadliness of the tubes, I looked for instant annihilation.

But it was evident in a moment that it was only as a precaution that the tubes were held upon us. For now, while a half-score of the Neptunians held Marlin and me firmly by the arms of our space-walkers, the one who had given the order came closer to us, clambered with his powerful multiple limbs upon the top of my space-walker, and gazed in through its vision-windows at me. To see those bulging, glassy and insect-like eyes outside the window so close to my own struck me through with a chilling horror greater than anything I had yet felt. I saw that the creature had discerned me inside the space-walker, had assured himself that creatures of life yet different from himself occupied the two cylinders. For in a moment he had clambered back down to the ground, and then as he uttered another sharp order, the creatures that held us were dragging us forward, toward the door of the compartment into which we had looked before.

Through that low door they dragged us in our space-walkers, and across the adjoining compartment toward one of the great upright cylinders resting there. In another moment the Neptunians had pulled us inside the door of that cylinder into its dark opening, and I saw the one who had given the orders following, with a half-dozen of his fellows. The others were dispersing to the other cylinders, and in a moment the door of our own slid clanging shut behind us. Then there was a hissing and throbbing of strange machinery in the dark interior of the cylinder about us, and at the same moment the leader of the Neptunians motioned to us to emerge from our space-walkers, having removed their own glowing ball-heaters.

I think that both Marlin and I hesitated for a long moment before complying with that command, yet we saw that upon us still were trained the tubes of the four Neptunians who guarded us, so reluctantly we threw open the lower doors of the space-walkers and emerged from them. As we did so, forgetful for the moment of the strange creatures about us, we gazed in amazed interest around us. The huge cylinder's interior, we saw, was divided into a half-dozen compartments by metal floors or ceilings set at intervals of ten or twelve feet from its bottom to its top. A light metal ladder ran up through openings in all of the those floors or divisions, and up that ladder now a few of the many-limbed Neptunians were hurrying toward the upper compartments. We ourselves were standing, with the Neptunian leader of the red-circle insignia, in the lowest or bottom compartment of the cylinder, his four tube-armed guards and a half-dozen green disk-bodied monsters about us.

That lowest compartment held great gleaming-cased mechanisms, from which came the throbbing that we had already heard, and that was so exactly similar to the throb of our space-flier's generators as to remove all doubt but that these were the similar generators of the cylinder. As our eyes roved about them the Neptunian leader uttered a staccato command, at the same time pointing with one of his seven limbs, up toward the ladder. His meaning was unmistakable, and at once Marlin and I stepped toward the ladder and began to climb upward on it, the tubes of the four watchful guards just beneath us as they followed. As we passed up that ladder, through the upper sections of the cylinder's interior, I saw vaguely the things within those sections.

One of them held the dissembled parts of the great cogged mechanisms we had seen them taking down and storing inside the cylinders. Another two or three sections held similar dissembled parts of differing machines that had evidently been taken from another part of the dead vast compartment-city beneath. We passed up through sections that held supplies and strange tank-like affairs, that seemed not unlike the batteries of our own space-flier, and then were climbing up into the topmost section of the cylinder. This was a section whose top and walls were set with so many windows as to make its sides seem quite transparent. And this topmost section, in which a pair of Neptunians already were standing, was quite apparently the control-section.

For at its center rose from its floor a thick metal pillar or standard, upon the top and sides of which were set a battery of dozens of small green studs, and around this were strange seats in which the two waiting Neptunians were now taking their places. As Marlin and I climbed into that uppermost section, the guards and the leader of the disk-bodied Neptunians behind us, we gazed wonderingly about, at the central control-standard and at the strange graduated scales with moving dots of light upon them, that were set here and there in the walls and that seemed recording instruments of one kind or another. Then the crimson-marked leader had given utterance to another sharp succession of snapping sounds, a swift command, at the same time motioning us to the side of the circular room, where were similar low, strange seats. In these we seated ourselves, the four Neptunians who watched us taking places on either side of us, and then as the leader took the remaining seat at the control-standard, we saw one of the other two seated there reach forth with strange quick limbs and touch a number of the studs in swift succession.

At once the great throbbing of the generators or mechanisms in the cylinder's lowest section intensified, and as Marlin and I gazed quickly outward through the windows about us we saw that now the other cylinders in the compartment were all closed and throbbing like this one. Then, as one of the Neptunians at the control-standard touched another stud, the cylinder in which we were rose swiftly upward and out of the great black-walled compartment, rose up smoothly over the dead compartment-city into the pale light of the Neptunian day, followed at once by the three other cylinders. The dim day about us was already waning, fading, as night crept across this huge world of silence and death, with its ceaseless rotation, but there remained still enough light for us to see far across the mighty maze of compartments that was the deserted and dead city. And now across that city the four cylinders were rushing, racing over it in horizontal position, the strange seats upon which we and the Neptunians were seated swinging in gimbal-like frameworks as the cylinder swung thus from vertical to horizontal.

Over the huge compartment-city our four cylinders flashed, then slowed and halted, as up from another point in it rose four more cylinders, the four that we had seen land in a different part of it, and whose occupants had discovered and captured us. Then all of the eight great cylinders, our own in the lead, were rising sharply upward, up toward the opening in the vast roof above, through which we had seen them come. As they shot up toward it, Marlin and I, glancing down and backward, could see, even as we had seen from our space-flier, the vast extent of the dead and deserted compartment-city, with its mechanisms and huge globes and high black intersecting walls lying now in such dusty silence and death. Yet it was only for a moment that we glanced back toward it, for now our eight cylinders were flashing up through the round opening in the huge roof, and out over that vast roof, seeming solid metal from above, that covered all of mighty Neptune. And as we flashed over it, now, I found for the first time opportunity to whisper to Marlin, beside me.

"They're leaving Neptune!" I whispered. "Where can they be going, Marlin? And what has happened to Whitely and Randall?"

He shook his head, answered in the same low tones. "Whitely and Randall have escaped, I hope. They had a small start on their pursuers—they may have eluded them here above Neptune——"

We were abruptly silent as the guards glanced suspiciously toward us with their bulging multiple eyes. And as the great cylinder and those behind shot on, the huge metal roof of Neptune below and the vast vapor-masses of its dense atmosphere stretched above us, I wondered if ever men had found themselves in the position that now was ours. Captured by monstrous disk-bodied beings of horror unutterable, flashing with them above the vast roof that sheathed Neptune and its dead, deserted and colossal compartment-city, to a destination of which we could not dream! And as that thought passed, another came, and I remembered the great mission that had brought us out here to the terrors of mighty Neptune, our great flight outward to find and put an end to the huge force-ray that was stabbing across the solar system and turning the sun ever faster, with every day bringing it nearer to the division that meant doom for almost all its universe. What chance was ours to accomplish that mission now, separated and captured as we were, not knowing even from what source the great ray was issuing, from what strange place these disk-bodied beings had come and to which they were now returning?