Course, lookout, and rank forgotten, the little crew of two stared into the narrow field of vision, set at its maximum magnification. The instruments showed that the enemy vessel was staying upon its original course. Very soon the torpedo came within range of the detectors of the hexans. But as Captain Czuv had foretold, the detection was a fraction of a second too late, rapidly as their screens responded, and the two men of Zbardk uttered together a short, fierce cry of joy as a brilliant flash of light announced the annihilation of the hexan vessel.

"But hold!" The observer stared into his screen. "Upon that same line, but now at constant velocity, there is still a very faint radiation, of a pattern I have never seen before."

"I think ... I believe ..." the captain was studying the pattern, puzzled. "It must be low frequency, low-tension electricity, which is never used, so far as I know. It may be some new engine of destruction, which the hexan was towing at such a distance that the explosion of our torpedo did not destroy it. Since there are no signs of hexan activity and since it will not take much fuel, we shall investigate that radiation."

Tail and port-side rockets burst into roaring activity and soon the plane was cautiously approaching the ma.s.s of wreckage, which had been the IPV _Arcturus_.

"Human beings, although of some foreign species!" exclaimed the captain, as his vision-ray swept through the undamaged upper portion of the great liner and came to rest upon Captain King at his desk.

Although the upper ultra-lights of the Terrestrial vessel had been cut away by the hexan plane of force, jury lights had been rigged, and the two commanders were soon trying to communicate with each other. Intelligible conversation was, of course, impossible, but King soon realized that the visitors were not enemies. At their pantomimed suggestion he put on a s.p.a.ce-suit and wafted himself over to the airlock of the Callistonian warplane. Inside the central compartment, the strangers placed over his helmet a heavily wired harness, and he found himself instantly in full mental communication with the Callistonian commander. For several minutes they stood silent, exchanging thoughts with a rapidity impossible in any language; then, dressed in s.p.a.ce-suits, both leaped lightly across the narrow gap into the still open outer lock of the terrestrial liner. King watched Czuv narrowly after the pressure began to collapse his suit, but the stranger made no sign of distress. He had been right in his a.s.surance that the extra pressure would scarcely inconvenience him. King tore off his helmet, issued a brief order, and soon every speaker in the _Arcturus_ announced:

"All pa.s.sengers and all members of the crew except lookouts on duty will a.s.semble immediately in Saloon Three to discuss a possible immediate rescue."

The subject being one of paramount interest, it was a matter of minutes until the full complement of two hundred men and women were in the main saloon, clinging to hastily rigged hand lines, closely packed before the raised platform upon which were King and Czuv, wired together with the peculiar Callistonian harness. To most of the pa.s.sengers, familiar with the humanity of three planets, the appearance of the stranger brought no surprise; but many of them stared in undisguised amazement at his childish body, his pale, almost colorless skin, his small, weak legs and arms, and his ma.s.sive head.

"Ladies and gentlemen!" Captain King opened the meeting. "I introduce to you Captain Czuv, of the scout cruiser _Bzarvk_, of the only human race now living upon the fourth large satellite of Jupiter, which satellite we know as Callisto. I am avoiding their own names as much as possible, because they are almost unp.r.o.nounceable in English or Interplanetarian.

This device that you see connecting us is a Callistonian thought transformer, by means of which any two intelligent beings can converse without language. Our situation is peculiar, and in order that you may understand fully what lies ahead of us, the captain will now speak to you, through me--that is, what follows will be spoken by Captain Czuv, of the _Bzarvk_, but he will be using my vocal organs."

"Friends from distant Tellus," King's voice went on, almost without a break, "I greet you. I am glad, for your sake as well as our own, that your vessel was able to destroy the hexan ship holding you captive, and whose crew would have killed you all as soon as they had landed your vessel and had read your minds. I regret bitterly that we can do so little for you, for only the representatives of a human civilization being exterminated by a race of highly intelligent monsters can fully realize how desirable it is for all the various races of humanity to a.s.sist and support each other. In order that you may understand the situation, it is necessary that I delve at some length into ancient history, but we have ample time. In about ..." he broke off, realizing that the two races had no thought in common in the measure of time.

"One-half time of rotation of Great Planet upon axis?" flashed from Czuv's brain, and "About five hours," King's mind flashed back.

"It will be about five hours before any steps can be taken, so that I feel justified in using a brief period for explanation. In the evolution of the various forms of life upon Callisto, two genera developed intelligence far ahead of all others. One genus was the human, as you and I; the other the hexan. This creature, happily unknown to you of the planets nearer our common sun, is the product of an entirely different evolution. It is a six-limbed animal, with a brain equal to our own--one perhaps in some ways superior to our own. They have nothing in common with humanity, however; they have few of our traits and fewer of our mental processes. Even we who have fought them so long can scarcely comprehend the chambers of horror that are their minds. Even were I able to paint a sufficiently vivid picture with words, you of Earth could not begin to understand their utter ruthlessness and inhumanity, even among themselves. You would believe that I was lying, or that my viewpoint was warped. I can say only that I hope most sincerely that none of you will ever get better acquainted with them."

"Ages ago, then, the human and the hexan developed upon all four of the major satellites of the Great Planet, which you know as Jupiter, and upon the north polar region of Jupiter itself. By what means the two races came into being upon worlds so widely separated in s.p.a.ce we know not--we only know it to be the fact. Human life, however, could not long endure upon Jupiter. The various human races, after many attempts to meet conditions of life there by variations in type fell before the hexans; who, although very small in size upon the planet, thrived there amazingly. Upon the three outer satellites humanity triumphed, and many hundreds of cycles ago the hexans of those satellites were wiped out, save for an occasional tribe of savages of low intelligence who lived in various undesirable portions of the three worlds. For ages then there was peace upon Callisto. Here is the picture at that time--upon Jupiter the hexans; upon Io hexans and humans, waging a ceaseless and relentless war of mutual extermination; upon the three outer satellites humanity in undisturbed and unthreatened peace. Five worlds, each ignorant of life upon any other.

"As I have said, the hexans of Jupiter were, and are, diabolically intelligent. Driven probably by their desire to see what lay beyond their atmosphere of eternal cloud, to the penetration of which their eyesight was attuned, they developed the s.p.a.ce-ship; and effected a safe landing, first upon the barren, airless moonlet nearest them, and then upon fruitful Io. There they made common cause with the hexans against the humans, and in s.p.a.ce of time Ionian humanity ceased to exist.

Much traffic and interbreeding followed between the hexans of Jupiter and those of Io, resulting in time in a race intermediate in size between the parent stocks and equally at home in the widely variant air pressures and gravities of planet and satellite. Soon their astronomical instruments revealed the cities of Europa to their gaze, and as soon as they discovered that the civilization of Europa was human, they destroyed it utterly, with the insatiable blood l.u.s.t that is their heritage.

"In the meantime the human civilizations of Ganymede and Callisto had also developed instruments of power. Observing the cities upon the other satellites, many scientists studied intensively the problem of s.p.a.ce navigation, and finally there was some commerce between the two outer satellites at favorable times. Finally, vessels were also sent to Io and to Europa, but none of them returned. Knowing then what to expect, Ganymede and Callisto joined forces and prepared for war. But our science, so long attuned to the arts of peace, had fallen behind lamentably in the devising of more and ever more deadly instruments of destruction. Ganymede fell, and in her fall we read our own doom.

Abandoning our cities, we built anew underground. Profiting from lessons learned full bloodily upon Ganymede, we resolved to prolong the existence of the human race as long as possible.

"The hexans were, and are masters of the physical science. They command the spectrum in a way undreamed of. Their detectors reveal etheric disturbances at unbelievable distances, and they have at their beck and call forces of staggering magnitude. Therefore in our cities is no electricity save that which is wired, shielded, and grounded; no broadcast radio; no source whatever of etheric disturbances save light--and our walls are fields of force which we believe to be impenetrable to any searching frequency capable of being generated.

Now I am able to picture to you the present.

"We are the last representatives of the human race in the Jovian planetary system. Our every trace upon the surface has been obliterated.

We are hiding in our holes in the ground, coming out at night by stealth so that our burrows shall not be revealed to the hexans. We are fighting for time in which our scientists may learn the secrets of power--and fearing, each new day, that the enemy may have so perfected their systems of rays that they will be able to detect us and destroy us, even in our underground and heavily shielded retreats, by means of forces even more incomprehensible than those they are now employing.

"Therefore, friends, you see how little we are able to do for you, we a race fighting for our very existence and doomed to extinction save for a miracle. We cannot take you to Callisto, for it is besieged by the hexans and the driving forces of your lifeboats, practically broadcast as they are, would be detected and we should all be destroyed long before we could reach safety. Captain King and I have pondered long and have been able to see only one course of action. We are drifting at constant velocity, using no power, and with all save the most vitally necessary machinery at rest. Thus only may we hope to avoid detection during the next two hours.

"Our present course will take us very close to Europa, which the hexans believe to be like Ganymede, entirely devoid of civilized life. Its original humanity was totally destroyed, and all its civilized hexans are finding shelter from our torpedoes upon Jupiter until we of Callisto shall likewise have been annihilated. The temperature of Europa will suit you. Its atmosphere, while less dense than that to which you are accustomed, will adequately support your life. If we are not detected in the course of the next few hours we can probably land upon Europa in safety, since its neighborhood is guarded but loosely. In fact, we have a city there, as yet unsuspected by the hexans, in which our scientists will continue to labor after Callisto's civilization shall have disappeared. We think that it will be safe to use your power for the short time necessary to effect a landing. We shall land in a cavern, in a crater already in communication with our city. In that cavern, instructed and aided by some of us, you will build a rocket vessel--no rays can be used because of the hexans--in which you will be able to travel to a region close enough to your earth so that you can call for help. You will not be able to carry enough fuel to land there--in fact, nearly all the journey will have to be made without power, traveling freely in a highly elongated orbit around the sun--but if you escape the hexans, you should be able to reach home safely, in time. It is for the consideration of this plan that this meeting has been called."

"Just one question," Breckenridge spoke. "The hexans are intelligent.

Why are they leaving Europa and Ganymede so unguarded that human beings can move back there and that we can land there, all undetected?"

"I will answer that question myself," replied King. "Captain Czuv did not quite do justice to his own people. It is true that they are being conquered, but for every human life that is taken, a thousand hexans die, and for every human ship that is lost, twenty hexan vessels are annihilated in return. While the hexans are masters of rays, the humans are equally masters of explosives and of mechanisms. They can hit a perfect score upon any target in free s.p.a.ce whose course and acceleration can be determined, at any range up to five thousand kilometers, and they have explosives thousands of times as powerful as any known to us. Ray screens are effective only against rays, and the hexans cannot destroy anything they cannot see before it strikes them.

So it is that all the hexan vessels except those necessary to protect their own strongholds, are being concentrated against Callisto. They cannot spare vessels to guard uselessly the abandoned satellites.

Because of the enormously high gravity of Jupiter the hexans there are safe from human attack save for ineffectual long-range bombardment, but Io is being attacked constantly and it is probable that in a few more years Io also will be an abandoned world. Some of you may have received the impressions that the hexans are to triumph immediately, but such an idea is wrong. The humans can, and will, hold out for a hundred years or more unless the enemy perfects a destructive ray of the type referred to. Even then, I think that our human cousins will hold out a long time.

They are able men, fighters all, and their underground cities are beautifully protected."

There was little argument. Most of the auditors could understand that the suggested course was the best one possible. The remainder were so stunned by the unbelievable events of the attack that they had no initiative, but were willing to follow wherever the more valiant spirits led. It was decided that no attempt should be made to salvage any portion of the _Arcturus_, since any such attempt would be fraught with danger and since the wreckage would be of little value. The new vessel was to be rocket driven and was to be built of Callistonian alloys.

Personal belongings were moved into lifeboats, doors were closed, and there ensued a painful period of waiting and suspense.

The stated hour was reached without event--no hexan scout had come close enough to them to detect the low-tension radiation of the vital machinery of the _Arcturus_, cut as it was to the irreducible minimum and quite effectively grounded as it was by the enormous ma.s.s of her shielding armor. At a signal from Captain Czuv the pilot of each lifeboat shot his tiny craft out into s.p.a.ce and took his allotted place in the formation following closely behind the _Bzarvk_, flying toward Europa, now so large in the field of vision that she resembled more a world than a moon. Captain King, in the Callistonian vessel, transmitted to Breckenridge the route and flight data given him by the navigator of the winged craft. The chief pilot, flying "point," in turn relayed more detailed instructions to the less experienced pilots of the other lifeboats.

Soon the surface of Europa lay beneath them; a rugged, cratered, and torn topography of mighty ranges of volcanic mountains. Most of the craters were cold and lifeless; but here and there a plume of smoke and steam betrayed the presence of vast, quiescent forces. Straight down one of those gigantic lifeless shafts the fleet of s.p.a.ce craft dropped--straight down a full two miles before the landing signal was given. At the bottom of the shaft a section of the rocky wall swung aside, revealing the yawning black mouth of a horizontal tunnel. At intervals upon its roof there winked into being almost invisible points of light. Along that line of lights the lifeboats felt their way, coming finally into a huge cavern, against one sheer metal wall of which they parked in an orderly row. Roll was called, and the terrestrials walked, as well as they could in the feeble gravity of the satellite, across the vast chamber and into a conveyance somewhat resembling a railway coach, which darted away as soon as the doors were shut. For hundreds of miles that strange tunnel extended, and as the car shot along door after door of natural rock opened before it, and closed as soon as it had sped through. In spite of the high velocity of the vehicle, it required almost two hours to complete the journey. Finally, however, it slowed to a halt and the Terrestrial visitors disembarked at a portal of the Europan city of the Callistonians.

"Attention!" barked Captain King. "The name of this city, as nearly as I can come to it in English, is _WRUZK_. 'Roosk' comes fairly close to it and is easier to p.r.o.nounce. We must finish our trip in small cars, holding ten persons each. We shall a.s.semble again in the building in which we have been a.s.signed quarters. The driver of each car will lead his pa.s.sengers to the council room in which we shall meet."

"Oh, what's the use--this is horrible, horrible--we might as well die!"

a nervous woman shrieked, and fainted.

"Such a feeling is, perhaps, natural," King went on, after the woman had been revived and quiet had been restored, "but please control it as much as possible. We are alive and well, and will be able to return to Tellus eventually. Please remember that these people are putting themselves to much trouble and inconvenience to help us, desperate as their own situation is, and conduct yourselves accordingly."

The rebuke had its effect, and with no further protest the company boarded the small cars, which shot through an opening in the wall and into a street of that strange subterranean city. Breckenridge, in the last car to leave the portal, studied his surroundings with interest as his conveyance darted through the gateway. More or less a fatalist by nature and an adventurer, of course, since no other type existed among the older s.p.a.cehounds of the IPC, he was intensely interested in every new phase of their experience, and was no whit dismayed or frightened.

He found himself seated in a narrow canoe of metal, immediately behind the pilot, who sat at a small control panel in the bow. Propelled by electro-magnetic fields above a single rail, upon lightly touching and noiseless wheels, the terrestrial pilot saw with keen appreciation the manner in which switch after switch ahead of them obeyed the impulses sent ahead from the speeding car. The streets were narrow and filled with monorails; pedestrians pursued their courses upon walks attached to the walls of the buildings, far above the level of the streets. The walls were themselves peculiar, rising as they did stark, unbroken, windowless expanses of metal, merging into and supporting a ma.s.sive roof of the same silvery metal. Walls and roof alike reflected a soft, yet intense, white light. Soon a sliding switch ahead of them shot in and simultaneously an opening appeared in the blank metal wall of a building. Through the opening the street-car flew, and as the pilot slowed the canoe to a halt, the door slid smoothly shut behind them.

Parking the car beside a row of its fellows, the Callistonian driver indicated that the Terrestrials were to follow him and led the way into a large hall. There the others from the _Arcturus_ were a.s.sembled, facing Captain King, who was standing upon a table.

"Fellow travelers," King addressed them, "our course of action has been decided. There are two hundred three of us. There will be twenty sections of ten persons, each section being in charge of one of the officers of the _Arcturus_. Doctor Penfield, our surgeon, a man whose intelligence, fairness, and integrity are unquestioned, will be in supreme command. His power and authority will be absolute, limited only by the Callistonian Council. He will work in harmony with the engineer, who is to direct the entire project of building the new vessel. Each of you will be expected to do whatever he can--the work you will be asked to do will be well within your powers, and you will each have ample leisure for recreation, study, and amus.e.m.e.nt, of all of which you will find unsuspected stores in this underground community. You will each be registered and studied by physicians, surgeons, and psychologists; and each of you will have prescribed for him the exact diet that is necessary for his best development. You will find this diet somewhat monotonous, compared to our normal fare of natural products, since it is wholly synthetic; but that is one of the minor drawbacks that must be endured. Chief Pilot Breckenridge and I will not be with you. In some small and partial recompense for what they are doing for us all, he and I are going with Captain Czuv to Callisto, there to see whether or not we can aid them in any way in the fight against the hexans. One last word--Doctor Penfield's rulings will be the products of his own well-ordered mind after consultation and agreement with the Council of this city, and will be for the best good of all. I do not antic.i.p.ate any refusal to cooperate with him. If, however, such refusal should occur, please remember that he is a despot with absolute power, and that anyone obstructing the program by refusing to follow his suggestions will spend the rest of his time here in confinement and will go back to Tellus in irons, if at all. In case Chief Pilot Breckenridge and I should not see you again, we bid you goodbye and wish you a safe voyage--but we expect to go back with you."

Brief farewells were said and captain and pilot accompanied Czuv to one of the little street-cars. Out of the building it dashed and down the crowded but noiseless thoroughfare to the portal. Signal lights flashed briefly there and they did not stop, but tore on through the portal and the tunnel, with increasing speed.

"Don't have to transfer to a big car, then?" asked Breckenridge.

"No," King made answer. "Small cars can travel these tubes as well as the large ones, and on much less power. In the city the wheels touch the rails lightly, not for support, but to make contacts through which traffic signals are sent and received. In the tunnels the wheels do not touch at all, as signaling is unnecessary--the tunnels being used infrequently and by but one vehicle at a time. No trolleys, tracks, or wires are visible, you notice. Everything is hidden from any possible visiray of the hexans."

"How about their power?"

"I don't understand it very well--hardly at all, in fact."

"It is quite simple." To the surprise of both Terrestrials, Czuv was speaking English, but with a strong and very peculiar accent; slighting all the vowels and accenting heavily the consonant sounds. "The car no longer requires my attention, so I am now free to converse. You are surprised at my knowing your language? You will speak mine after a few more applications of the thought exchanger. I am speaking with a vile accent, of course, but that is merely because my vocal organs are not accustomed to making vowel sounds. Our power is obtained by the combustion of gases in highly efficient turbines. It is transmitted and used as direct current, our generator and motors being so constructed that they can produce no etheric disturbances capable of penetrating the shielding walls of our city. The city was built close to deposits of coal, oil, and gas of sufficient amount to support our life for thousands of years; for from these deposits come power, food, clothing, and all the other necessities and luxuries of our lives. Strong fans draw air from various extinct craters, force it through ventilating ducts into every room and recess of the city, and exhaust it into the shaft of a quiescent volcano, in whose gaseous outflow any trace of our activities is, of course, imperceptible. For obvious reasons no rockets or combustion motors are used in the city proper."

Thus Captain Czuv explained to the Terrestrials his own mode of life, and received from them in turn full information concerning Earthly life, activity, and science. Long they talked, and it was almost time to slow down for the journey's end when the Callistonian brought the conversation back to their immediate concerns.

"My lieutenant and I were upon a mission of some importance, but it is more important to take you to Callisto, for there may be many things in which you can help us. Not in rays--we know all the vibrations you have mentioned and several others. The enemy, however, is supreme in that field, and until our scientists have succeeded in developing ray-screens, such as are used by the hexans, it would be suicidal to use rays at all. Such screens necessitate the projection of pure, yet dirigible, forces--you do not have them upon your planet?"

"No, and so far as I know such screens are also unknown upon Mars and Venus, with whose inhabitants we are friendly."