Grimly Buck Kendall looked at the reports. McLaurin stood beside him, Devin sat across the table from him. "What do you make of it, Buck?" asked the Commander.
"That we have just one island of resistance left on the Jovian worlds. And that will, I fear, vanish. They haven't finished with their arsenal by any means."
"But what was it, man, what was it that ruined those ships?"
"Vibration. Somehow--Lord only knows how it's done--they can project electric fields. These projected fields are oscillated, and they are tuned in with some parts of the ship. I suspect they are crystals of the metals. If they can start a vibration in the crystals of the metal--that's fatigue, metal fatigue enormously speeded. You know how a quartz crystal oscillator in a radio-control apparatus will break, if you work it on a very heavy load at the peak? They simply smash the crystals of metal in the same way. Only they project their field."
"Then our toughest metals are useless? Can't something tough, rather than hard, like copper or even silver for instance, stand it?"
"Calcium metal's the toughest going--and even that would break under the beating those ships give it. The only way to withstand it is to have such a mass of metal that the oscillations are damped out. But--"
The set tuned in on the IP station on Europa was speaking again. "The ships are returning. There are one hundred and twenty-nine by accurate count. Jorgsen reports that telescopic observation of the dead on the fallen cruiser show them to be a completely un-human race! They are of mottled coloring, predominately grayish brown. The ships are returning. They have divided into ten groups, nine groups of two each, and a main body of the rest of the fleet. The group of eighteen is descending within range, and we are focusing our beams on them--"
Out by Europa, ten great UV beams were stabbing angrily toward ten great interstellar ships. The metal of the hulls glowed brilliant, and distorted slowly as the thick walls softened under the heat, and the air behind pressed against it. Grimly the ten ships came on. Torpedoes were being launched, and exploded, and now they had no effect, for the Mirans within were protected.
The eighteen grouped ships separated, and arranged themselves in a circle around the fort. Suddenly one staggered as a great puff of gas shot out through the thin atmosphere of Europa to flare brilliantly in the lash of the stabbing UV beam. Instantly the ship righted itself, and labored upward. Another dropped to take its place--
And the great walls of the IP fort suddenly groaned and started in their welded joints. The faint, whispering rustle of the crumbling beam was murmuring through the station. Engineers shouted suddenly as meters leapt the length of their scales, and the needles clicked softly on the stop pins. A thin rustle came from the atostors grouped in the great power room. "Spirits of Space--a revolving magnetic field!" roared the Chief Technician. "They're making this whole blasted station a squirrel cage!"
The mighty walls of eight-foot metal shuddered and trembled. The UV beams lashed out from the fort in quivering arcs now, they did not hold their aim steady, and the magnetic shield that protected them from atomic bombs was working and straining wildly. Eighteen great ships quivered and tugged outside there now, straining with all their power to remain in the same spot, as they passed on from one to another the magnetic impulses that were now creating a titanic magnetic vortex about the fort.
"The atostors will be exhausted in another fifteen minutes," the Chief Technician roared into his transmitter. "Can the signals get through those fields, Commander?"
"No, Mac. They've been stopped, Sparks tells me. We're here--and let's hope we stay. What's happening?"
"They've got a revolving magnetic field out there that would spin a minor planet. The whole blasted fort is acting like the squirrel cage in an induction motor! They've made us the armature in a five hundred million horsepower electric motor."
"They can't tear this place loose, can they?"
"I don't know--it was never--" The Chief stopped. Outside a terrific roar and crash had built up. White darts of flame leapt a thousand feet into the air, hurling terrific masses of shattered rock and soil.
"I was going to say," the Chief went on, "this place wasn't designed for that sort of a strain. Our own magnetic field is supporting us now, preventing their magnetic field from getting its teeth on metal. When the strain comes--well, they're cutting loose our foundation with atomic bombs!"
Five UV beams were combined on one interstellar ship. Instantly the great machine retreated, and another dropped in to take its place while the magnetic field spun on, uninterruptedly.
"Can they keep that up long?"
"God knows--but they have a hundred and more ships to send in when the power of one gives out, remember."
"What's our reserve now?"
The Chief paused a moment to look at the meters. "Half what it was ten minutes ago!"
Commander Wallace sent some other orders. Every torpedo tube of the station suddenly belched forth deadly, fifteen-foot torpedoes, most of them mud-torpedoes, torpedoes loaded with high explosive in the nose, a delayed fuse, and a load of soft clinging mud in the rear. The mud would flow down over the nose and offer a resistance foot-hold for the explosive which empty space would not. Four hundred and three torpedoes, equipped with anti-magnetic apparatus darted out. One hundred and four passed the struggling fields. One found lodgement on a Miran ship, and crushed in a metal wall, to be stopped by a bulkhead.
The Chief engineer watched his power declining. All ten UV beams were united in one now, driving a terrible sword of energy that made the attacked ship skip for safety instantly, yet the beams were all but useless. For the Miran reserves filled the gap, and the magnetic tornado continued.
For seventeen long minutes the station resisted the attack. Then the last of the strained mercury flowed into the receivers, and the vast power of the atostors was exhausted. Slowly the magnetic fields declined. The great walls of the station felt the clutching lines of force--they began to heat and to strain. A low, harsh grinding became audible over the roar of the atomic bombs. The whole structure trembled, and jumped slightly. The roar of bombs ceased suddenly, as the station jerked again, more violently. Then it turned a bit, rolled clumsily. Abruptly it began to spin violently, more and more rapidly. It started rolling clumsily across the plateau--
A rain of atomic bombs struck the unprotected metal, and the eighth breached the walls. The twentieth was the last. There was no longer an IP station on Europa.
"The difference," said Buck Kendall slowly, when the reports came in from scout-ships in space that had witnessed the last struggle, "between an atomic generator and an atomic power-store, or accumulator, is clearly shown. We haven't an adequate source of power."
McLaurin sighed slowly, and rose to his feet. "What can we do?"
"Thank our lucky stars that Faragaut here, and I, bought up all the mercury in the system, and had it brought to Earth. We at least have a supply of materials for the atostors."
"They don't seem to do much good."
"They're the best we've got. All the photocells on Earth and Venus and Mercury are at present busy storing the sun's power in atostors. I have two thousand tons of charged mercury in our tanks here in the 'Lunar Bank.'"
"Much good that will do--they can just pull and pull and pull till it's all gone. A starfish isn't strong, but he can open the strongest oyster just because he can pull from now on. You may have a lot of power--but."
"But--we also have those new fifteen-foot UV beams. And one fifteen-foot UV beam is worth, theoretically, nine five-foot beams, and practically, a dozen. We have a dozen of them. Remember, this place was designed not only to protect itself, but Earth, too."
"They can still pull, can't they?"
"They'll stop pulling when they get their fingers burned. In the meantime, why not use some of those IP ships to bring in a few more cargoes of charged mercury?"
"They aren't good for much else, are they? I wonder if those fellows have anything more we don't know?"
"Oh, probably. I'm going to work on that crumbler thing. That's the first consideration now."
"Why?"
"So we can move a ship. As it is, even those two we built aren't any good."
"Would they be anyway?"
"Well--I think I might disturb those gentlemen slightly. Remember, they each have a nose-beam eighteen feet across. Exceedingly unpleasant customers."
"Score: Strangers; magnetic field, atomic bombs, atomic power, crumbler ray. Home team; UV beams."
Kendall grinned. "I'd heard you were a pessimistic cuss when battle started--"
"Pessimistic, hell, I'm merely counting things up."
"McClellan had all the odds on Lee back in the Civil War of the States--but Lee sent him home faster than he came."
"But Lee lost in the end."
"Why bring that up? I've got work to do." Still smiling, Kendall went to the laboratory he had built up in the "Lunar Bank." Devin was already there, calculating. He looked unhappy.
"We can't do anything, as far as I can see. They're using an electric field all right, and projecting it. I can't see how we can do that."
"Neither can I," agreed Kendall, "so we can't use that weapon. I really didn't want to anyway. Like the neutron gun which I told Commander McLaurin would be useless as a weapon, they'd be prepared for it, you can be sure. All I want to do is fight it, and make their projection useless."
"Well, we have to know how they project it before we can break up the projection, don't we?"
"Not at all. They're using an electric field of very high frequency, but variable frequency. As far as I can see, all we need is a similar variable electric field of a slightly different frequency to heterodyne theirs into something quite harmless."
"Oh," said Devin. "We could, couldn't we? But how are you going to do that?"
"We'll have to learn, that's all."
Buck Kendall started trying to learn. In the meantime, the Mirans were taking over Jupiter. There were three IP stations on the planet itself, but they were vastly hindered by the thick, almost ultra-violet-proof atmosphere of Jupiter. Their rays were weak. And the magnetic fields of the Mirans were unaffected. Only their atomic bombs were hindered by the heavier gravity that pulled the rocks back in place faster than the bombs could throw them out. Still--a few hours of work, and the IP stations on Jupiter had rolled wildly across the flat plains of the planet like dented cans, to end in utter destruction.
The Mirans had paid no attention to the fleeing passenger and freighter ships that left the planet, loaded to the utmost with human cargo, and absolutely no freight. The IP fleet had to go to their rescue with oxygen tanks to take care of the extra humans, but nearly three-quarters of the population of Jupiter, a newly established population, and hence a readily mobile one, was saved. The others, the Mirans did not bother with particularly except when they happened to be near where the Mirans wanted to work. Then they were instantly destroyed by atomic bombing, or gamma rays.
The Mirans settled almost at once, and began their work of finding on Jupiter the badly needed atomic fuels. Machines were set up, and work begun, Mirans laboring under the gravity of the heavy planet. Then, fifty ships swam up again, reloaded with fuel, and with crews consisting solely of uninjured warriors, and started for Mars.
Mars was half way between her near conjunction and her maximum elongation with respect to Jupiter at that time. The Mirans knew their business though, for they started in on the IP station on Phobos. They were practiced by this time, and this IP station had only seven five-foot beams. In half an hour that station fell, and its sister station on Deimos followed. Three wounded ships returned to Jupiter, and ten new ships came out. The attack on Mars itself was started.
Mars was a different proposition. There were thirty-two IP stations here, one of them nearly as powerful as the Lunar Bank station. It was equipped with four of the huge fifteen-foot beams. And it had fifteen tons of mercury, more than seven-eighths charged. The Mars Center Station was located a short ten miles from the Mars Center City, and under the immediate orders of the IP heads, Mars Center City had been vacated.
For two days the Mirans hung off Mars, solidifying their positions on Phobos and Deimos. Then, with sixty-two ships, they attacked. They had made some very astute observations, and they started on the smaller stations just beyond the range of the Mars Center Station. Naturally, near so powerful a center, these stations had never been strong. They fell rapidly. But they had been counted on by Mars Center as auxiliary supports. McLaurin had sent very definite orders to Mars Center forbidding any action on their part, save gathering of power-supplies.
At last the direct attack on Mars Center was launched. For the first time, the Mirans saw one of the fifteen-foot beams. Mars' atmosphere is thin, and there is little ozone. The ultra-violet beams were nearly as effective as in empty space. When the Mirans dropped their ships, a full thirty of them, into the circle formation, Mars Center answered at once. All four beams started.
Those fifteen-foot beams, connected directly to huge atostor release apparatus, delivered a maximum power of two and three-quarter billion horsepower, each. The first Miran ship struck, sparkled magnificently, and a terrific cascade of white-hot metal rolled down from its nose. The great ship nosed down and to the left abruptly, accelerated swiftly--and crashed with tremendous energy on the plain outside of Mars Center City. White, unwavering flames licked up suddenly, and made a column five hundred feet high against the dark sky. Then the wreck exploded with a violence that left a crater half a mile across.
Three other ships had been struck, and were rapidly retreating. Another try was made for the ring formation, and four more ships were wounded, and replaced. The ring did not retreat, but the great magnetic field started. Atomic and gamma ray bombs started now, flashing sometimes dangerously close to the station as its magnetic field battled the rotating field of the ships. The four greater beams, and many smaller ones were in swift and angry action. Not more than a ten-second exposure could be endured by any one ship, before it must retreat.
For five minutes the Mirans hung doggedly at their task. Then, wisely, they retreated. Of the fleet, not more than seven ships remained untouched. Mars Center Station had held--at what cost only they knew. Five hundred tons of their mercury had been exhausted in that brief five minutes. One hundred tons a minute had flowed into and out of the atostor apparatus. Mars Center radioed for help, when the fleet lifted.
There was one other station on Mars that stood a good chance of survival, Deenmor Station, with three of the big beams installed, and apparatus for their fourth was in the station, and being rapidly worked over. McLaurin did a wise and courageous thing, at which every man on Mars cursed. He ordered that all IP stations save these two be deserted, and all mercury fuel reserves be moved to Deenmor and Mars Center.
The Mirans could not land on the North Western section of Mars, nor in the South Central region. Therefore Mars was not exactly habitable to Miran ships, because the great beams had been so perfectly figured that they were effective at a range of nearly twelve hundred miles.
Deenmor station was attacked--but it was a half-hearted attack, for Mirans were becoming distinctly skittish about fifteen-foot UV beams. Two badly blistered ships--and the Mirans retreated to Jupiter. But Mira held Phobos and Deimos. In two weeks, they had set up cannon there, and proved themselves accurate long-range gunners. Against the feeble attraction of Deimos, and with Mars' gravity to help them, they began bombarding the two stations, and anything that attempted to approach them, with gamma and atomic explosive bombs. Meanwhile they amused themselves occasionally by planting a gamma-ray bomb in each of Mars' major cities. They made Mars uninhabitable for Solarians as well as for Mirans, at least until the deadly slow-action atomic explosives wore off, or were removed.
Then the Mirans, after a lapse of three weeks while they dug in their toes on Jupiter, prepared to leap. Earth was the next goal. Miran scout-ships had been sent out before this--and severely handled by the concentrated fleets of the IP that hung grimly off Earth and Luna now. But the scouts had learned one thing. Mirans could never hope to attain a firm grasp on Earth while terribly armed Luna hung like a Sword of Damocles over their heads. Further, attack on Earth directly would be next to impossible, for, thanks to Faragaut's Interplanetary Company, nearly all the mercury metal in the system was safely lodged on Earth, and saturated with power. Every major city had been equipped with great UV apparatus. And neutron guns in plenty waited on small ships just outside the atmosphere to explode harmlessly any atomic or gamma bombs Miran ships might attempt to deposit.
An attack on Luna was the first step. But that terrible, gigantic fort on Luna worried them. Yet while that fort existed, Earth ships were free to come and go, for Mirans could not afford to stand near. At a distance of twenty thousand miles, small Miran ships had felt the touch of those great UV beams.
Finally, a brief test-attack was made, with an entire fleet of one hundred ships. They drew almost into position, faster than light, faster than the signaling warnings could send their messages. In position, all those great ships strained and heaved at the mighty magnetic vortex that twisted at the field of the fort. Instantly, twelve of the fifteen-foot UV beams replied. And--two great UV beams of a size the Mirans had never seen before, beams from the two ships, "S Doradus" and "Cepheid."
The test-attack dissolved as suddenly as it had come. The Mirans returned to Jupiter, and to the outer planets where they had further established themselves. Most of the Solar system was theirs. But the Solarians still held the choicest planets--and kept the Mirans from using the mild-temperatured Mars.
