The other carrier, too, was shooting planes into the air like bullets from a gun. The American Mediterranean fleet was putting out to sea at emergency-speed, getting every flying craft aloft that could be gotten away. A cruiser swung a peculiar crane-like arm, there was a puff of smoke and a plane came into being. The crane retracted. Another plane. A third.

The fleet was out of the harbor, speeding at thirty knots, with destroyers weaving back and forth at higher speeds still. There were barges left behind in the harbor with sailors in them,--sh.o.r.e-parties or details who swore bitterly when they were left behind. They surged up and down on the melee of waves the fleet left behind in its hasty departure.

On the fleet itself there was a brisk tenseness as it sped away from the land. Vesuvius still loomed high, but the city dwindled to a mere blinking ma.s.s of white specks which were its buildings. The sea was aglitter with sunlight reflected from the waves. There was the smell of salt air.

Men began to take cryptic measures for the future. They strung cables across the deck from side to side. Arresting gear for planes which would presently land.

Their special ensign found Coburn and Janice. "I'm supposed to stay with you," he explained politely. "I thought I could be of use. I'm really attached to another ship, but I was on board because of the ha.s.sle last night."

Coburn said: "This would be invader stuff, wouldn't it?"

The ensign shrugged. "Apparently. You heard what the radar said.

Something at three hundred thousand feet, descending rapidly. It's not a human-built ship. Anyway, we've sent up all our planes. Jets will meet it first, at fifty thousand. If it gets through them there are ... other measures, of course."

"This one beats me!" said Coburn. "Why?"

The ensign shrugged again. "They tried for you last night."

"I'm not that important, to them or anybody else. Or am I?"

"I wouldn't know," said the ensign.

"I don't know anything I haven't told," said Coburn grimly, "and the creatures can't suppress any information by killing me now. Anyhow, if they'd wanted to they'd have done it."

A dull, faint sound came from high overhead. Coburn stepped out from under the shelter of the upper works of the island. He stared up into the sky. He saw a lurid spot of blue-white flame. He saw others. He realized that all the sky was interlaced with contrails--vapor-trails of jet-planes far up out of sight. But they were fine threads. The jets were up very high indeed. The pin-points of flame were explosions.

"Using wing-rockets," said the ensign hungrily, "since fifty-calibres did no good last night, until one made a lucky hit. Rockets with proximity fuses. Our jets don't carry cannon."

There were more explosions. There was a bright glint of reflected sunshine. It was momentary, but Coburn knew that it was from a flat, bright s.p.a.ce-ship, which had tilted in some monstrously abrupt maneuver, and the almost vertical sunshine shone down from its surface.

The ensign said in a very quiet voice: "The fight's coming lower."

There was a crashing thump in the air. A battleship was firing eight-inch guns almost straight up. Other guns began.

Guns began to fire on the carrier, too, below the deck and beyond it.

Concussion waves beat at Coburn's body. He thrust Janice behind him to shield her, but there could be no shielding.

The air was filled with barkings and snarlings and the unbelievably abrupt roar of heavy guns. The carrier swerved, so swiftly that it tilted and swerved again. The other ships of the fleet broke their straight-away formation and began to move in bewildering patterns. The blue sea was criss-crossed with wakes. Once a destroyer seemed to slide almost under the bow of the carrier. The destroyer appeared unharmed on the other side, its guns all pointed skyward and emitting seemingly continuous blasts of flame and thunder.

The ensign grabbed Coburn's shoulder and pointed, his hands shaking.

There was the Invader ship. It was exactly as Coburn had known it would be. It was tiny. It seemed hardly larger than some of the planes that swooped at it. But the planes were drawing back now. The shining metal thing was no more than two thousand feet up and it was moving in erratic, unpredictable darts and dashes here and there, like a dragon-fly's movements, but a hundred times more swift. Proximity-fused sh.e.l.ls burst everywhere about it. It burst through a still-expanding puff of explosive smoke, darted down a hundred feet, and took a zig-zag course of such violent and angular changes of position that it looked more like a streak of metal lightning than anything else.

It was down to a thousand feet. It shot toward the fleet at a speed which was literally that of a projectile. It angled off to one side and back, and suddenly dropped again and plunged crazily through the maze of ships from one end to the other, no more than fifty feet above the water and with geysers of up-flung sea all about it from the sh.e.l.ls that missed.

Then it sped away with a velocity which simply was not conceivable. It was the speed of a cannonball. It was headed straight toward a distant, stubby, draggled tramp-steamer which plodded toward the Bay of Naples.

It rose a little as it flew. And then it checked, in mid-air. It hung above the dumpy freighter, and there were salvoes of all the guns in the fleet. But at the flashes it shot skyward. When the sh.e.l.ls arrived and burst, it was gone.

It could still be sighted as a spark of sunlight shooting for the heavens. Jets roared toward it. It vanished.

Coburn heard the ensign saying in a flat voice: "If that wasn't accelerating at fifteen Gs, I never saw a ship. If it wasn't accelerating at fifteen Gs ..."

And that was all. There was nothing else to shoot at. There was nothing else to do. Jets ranged widely, looking for something that would offer battle, but the radars said that the metal ship had gone up to three hundred miles and then headed west and out of radar range. There had not been time for the French to set up paired radar-beam outfits anyhow, so they couldn't spot it, and in any case its course seemed to be toward northern Spain, where there was no radar worth mentioning.

Presently somebody noticed the dingy, stubby, draggled tramp steamer over which the Invaders' craft had hovered. It was no longer on course.

It had turned sidewise and wallowed heavily. Its bow pointed successively to every point of the compa.s.s.

It looked bad. Salvoes of the heaviest projectiles in the Fleet had been fired to explode a thousand feet above it. Perhaps--

A destroyer went racing to see. As it drew near--Coburn learned this later--it saw a man's body hanging in a sagging heap over the railing of its bridge. There was n.o.body visible at the wheel. There were four men lying on its deck, motionless.

The skipper of the destroyer went cold. He brought his ship closer. It was not big, this tramp. Maybe two thousand tons. It was low in the water. It swayed and surged and wallowed and rolled.

Men from the destroyer managed to board it. It was completely unharmed.

They found one small sign of the explosions overhead. One fragment of an exploded sh.e.l.l had fallen on board, doing no damage.

Even the crew was unharmed. But every man was asleep. Each one slumbered heavily. Each breathed stertorously. They could not be awakened. They would need oxygen to bring them to.

A party from the destroyer went on board to bring the ship into harbor.

The officer in charge tried to find out the ship's name.

There was not a doc.u.ment to be found to show what the ship's name was or where it had come from or what it carried as cargo. That was strange.

The officer looked in the pockets of the two men in the wheel house.

There was not a single identifying object on either of them. He grew disturbed. He made a really thorough search. Every sleeping man was absolutely anonymous. Then--still on the way to harbor--a really fine-tooth-comb examination of the ship began.

Somebody's radium-dial watch began to glow brightly. The searchers looked at each other and went pale. They hunted frantically, fear making them clumsy.

They found it. Rather--they found them.

The stubby tramp had an adequate if rather clumsy atomic bomb in each of its two holds. The lading of the ship was of materials which--according to theory--should be detonated in atomic explosion if an atomic bomb went off nearby. Otherwise they could not be detonated.

The anonymous tramp-steamer had been headed for the harbor of Naples, whose newspapers--at least those of a certain political party--had been screaming of the danger of an atomic explosion while American warships were anch.o.r.ed there.

It was not likely that two atom bombs and a shipload of valuable secondary atomic explosive had been put on a carefully nameless ship just to be taken for a ride. If this ship had anch.o.r.ed among the American fleet and if it had exploded in the Bay of Naples ...

The prophecies of a certain political party would seem to have been fulfilled. The American ships would be destroyed. Naples itself would be destroyed. And it would have appeared that Europeans who loved the great United States had made a mistake.

It was, odd, though, that this ship was the only one that the Invaders'

flying craft had struck with its peculiar weapon.

VI