by Various
It arced through the sunlight, went spinning down, became a dot, its screaming faded. Then something synchronized within it, and it was gone--in a burst of weird, bluish light, whose fangs forked upwards for a second, their unearthly flash dimming even the sunlight, and then were gone, too....
* * * * *
Chris found that his whole body was shaking. For a moment he stood there with his masked face through the port.
"Damn close," he muttered. "But what was it that left the box here?"
Then he jarred against the side of the car as the ship swung and came back to realization of what was needed to be done, and done at once. He shifted his gaze, drew his head back, and thrust it forth again, staring.
"Good Lord!" he cried. "That plane's come back!"
His own craft was not alone under the rack. The same mysterious machine hung there again, its cockpit empty, and the automatic spider ladder was stretched down to it from the trap-door in the dirigible above.
"Whatever flies it is aboard now." Chris thought aloud. "But it got back too late to stop me. Well, this time--"
He felt uneasy, however, almost powerless. What was this thing that had wiped out the crews of two dirigibles with deadly gas, and wrecked one of them? He spun around. The control car looked the same. But what might be moving in it?...
Chris carried no gun; but he extracted the service repeater from the holster of a body at his feet. Gripping it, he leaped to the helm of the dirigible. It was the work of a moment to clamp on the mechanical "iron mike," which steadied the ZX-1's mad swaying and leveled her ahead in a dead straight course. He could not cut down her speed, unless he went to each one of the hull-enclosed engine stations, and more urgent work awaited before he could afford to do that--work of sending out an S.O.S. before the weird, unseen killer and wrecker came to grips with him.
Though seeming hours, only minutes had passed since he had tooled his scout into the rack. Ahead, he could see the smudge of the Black Fleet's smoke on the horizon. Not so very far away, but a lot could happen in the distance still separating dirigible and surface craft.
* * * * *
He ran back into the radio-telephone cubby, which was a division of the control car. The operator was sprawled there, limp in his seat before the shining, switch-studded panel. Chris removed the head-gear of ear-phones: then he hauled one of the cubby's port-holes open, letting in a rush of cleansing air. His fingers sped quickly over the panel; a row of tubes glowed; the machinery hummed. Chris jerked off his mask.
A last faint odor was present, but he hardly noticed it, for his lips were at the mouthpiece and he was thrusting out a call for help.
"ZX-1 calling ... ZX-1 calling ... ZX-1--Hello!"
An answer from the flagship of the Black Fleet ahead had sounded.
"This is Travers, pilot on the ZX-1, speaking. We're coming dead for you; full speed; you'll see us in minutes. Get some planes with men capable of handling the dirigible up here immediately. The whole crew's been laid out by gas; there was a contrivance planted aboard to blow up the ship and send it down in flames as the ZX-2 was. The thing that did it--"
Crack!
A gun barked out from behind; something crashed and splintered on the radio panel. Chris felt a white-hot needle sear along the side of his head. His brain reeled; with everything dancing queerly before him in splotches of gray and black he toppled down off the seat, knowing the radio-telephone had been put out of commission by the cessation of sound in the ear-phones clamped to him.
He gripped his consciousness hard. It was like a delirium: he was lying sprawled beside the seat, twisted round so that he saw, hanging in the cubby's entrance door, an automatic, dribbling a wisp of smoke--the automatic that had just fired, but hanging there by itself, held by something he could not see!
He was only half conscious, for the scorching pain along his head was throbbing his brain dizzily, but he realized that the service repeater he had taken from the control car lay by his side, within easy reach. But, while on the verge of risking a wild grab for it, he heard a voice, speaking very softly and with a slight thickness of accent.
"Do not move," it said. "I fire if you do. Now, listen: What did you do with the box that you found? Tell me quick, or die."
It was fantastic, unreal. There was--nothing, and yet a man, living, breathing, but invisible, was speaking! Chris could not understand; but it was at least a little relief to know he had a human to deal with. For with humans, strategy can be used....
* * * * *
He groaned. He saw plainly that the unseen marauder had been aboard when he had thrown the box over, and thus had not seen it explode in midair: did not know whether it had been tossed out or merely rendered harmless by being tampered with. If only the latter, it could be quickly repaired and set again. That must be the invisible man's reasoning.
Again Chris groaned. He moved an arm weakly and whispered:
"Can't speak much. Come closer."
The service repeater was very close now to his right hand. And he felt a thrill when he saw the automatic come forward through the air, descend, and pause right next to his head. He sensed a man close behind him, and he heard:
"Well? Tell me, quick. Did you throw it over, or--?"
"Don't shoot!" Chris groaned. "I'll tell you. I didn't--throw it over. I took it apart to get the secret of it. I put it--there."
He pointed feebly with his right hand, thus leading the invisible man to turn his head. His legs braced imperceptibly. And then:
"Like hell!" roared Chris Travers, and shot his whole weight backwards, grasping the service gun, whipping it around and yanking the trigger three times at the same instant.
Shooting at nothing! But, even above the bunched roar of the explosions, there pierced out a howl of agony that died quickly to a sobbing moan. Chris saw the automatic drop to the floor, felt the invisible body he had crashed into jerk away. He jumped to his feet, clutched at that body, and caught thin air. He swung around, listening, the service repeater in his hand.
Out of the air somewhere before him there came the sound of low, racking gasps, and also the slow noise of feet dragging heavily towards the cubby's door, towards the ladder that led up to the fore-and-aft cat-walk.
Chris sprang, slashing the butt of the gun downwards. The lead was false. He hurtled jarringly into the door jamb, the gun thumping against the floor. The wind was knocked from him; the nausea of his wound swept him again with a surge of dizziness. But the painful scuffle of unseen feet ahead pulled him up once more; like a punch-drunk fighter he staggered out from the cubby to the ladder and hauled himself up the steps. He half-fell at the top, but his mind was clearing; and as he swayed there he knew what he had to do--saw the duty that lay before him....
More slowly, he crawled after the dragging footsteps and the gasps of the invisible raider, following them through the vast dimness of the interior of the dirigible ZX-1.
* * * * *
The chief operator on duty in the flagship of the Black Fleet swung round in his seat and yelled through into the bridge of the massive battleship:
"Urgent, sir! From the ZX-1!"
A moment later the captain of the ship, for the fleet's admiral was out in a launch inspecting what little of the fallen ZX-2 was still floating on the surface, was at the operator's side, listening amazedly.
The operator read off, word for word, what Chris Travers had sent. "... There was a contrivance planted aboard to blow up the ship and send it down in flames as the ZX-2 was. The thing that did it is--" he finished, and fell silent on that uncompleted sentence.
The captain's lined face expressed incredulity. "My God!" he burst out. "First the ZX-2, now-- That all?"
"Yes, sir. I can't get any answer or connection."
They stared at each other. Finally the captain spluttered:
"Is some maniac loose in this fleet? Don't sit there like a fool, man! Get in touch with the Saratoga; tell 'em what you received; tell 'em to send some men up to that dirigi
ble, wherever she is. We can't lose both of them!"
The operator's fingers skipped nimbly; even while he was speaking into the microphone, the red-faced captain had rushed back into the control bridge and was roaring:
"Signal the Admiral back here! Hurry!"
* * * * *
Things moved quickly then; small things, but significant. A casual eye glancing over the ranks of the Black Fleet as it lay around the scene of the tragedy, waiting for orders, would not have noticed any difference. The launch containing the fleet's admiral, which had been fussing about with its load of officers and various dignitaries, suddenly wheeled and pointed back for the mammoth flagship, in response to swift signals from the arms of a gob on her bridge; and, on the broad landing deck of the carrier, Saratoga, two three-seater planes, equipped with automatic clamps for a dirigible's rack, were wheeled up to the line.
Their props were spun over. But even before their cockpits had been filled, an officer on the bridge of the flagship, and a dozen others throughout the fleet, cried:
"There she is!"
Over the eastern horizon, a gleaming sliver in the sunlight, thundered the ZX-1, straight for the array of the Black Fleet. Only a few men were aware of the drama-fraught message which had come down from her radio cubby, but her growing shape commanded the eyes of every sailor and officer alike who had time to watch. A few telescopic sights were trained on her as she bellowed ahead; the keen old eyes of a very perplexed and puzzled admiral were at one of them.
"Two planes hanging from her rack," he muttered, half to himself and half to the officers standing around him. "Both Navy. Say, they're dropping off! Not coming this way, either. Going northeast. Fast, too. Can't see 'em any more.... Those men getting up from the Saratoga? Good. We'll find out something soon. Here she comes!"
Closer and closer roared the dirigible. Two planes from the Saratoga were swooping up to enter her rack, but the other two planes that shortly before had been suspended from it were gone--already vanished into the northeast.
"Don't understand this at all!" said the Admiral of the Black, or Pacific, Fleet of the United States Navy.
* * * * *
Things had broken well, Chris Travers considered. He had only wounded the invisible raider; but, luckily, had wounded him badly, so that, evidently, just one object was in the man's mind: to get back to where he came from, to where he could find help. He seemed oblivious of the scout that was following behind at the full speed of its mighty rotary motor, following him to his base, wherever it was.
"Just as well I didn't kill him," Chris muttered.
The rush of wind had cleared his brain; his faculties were steady and normal. Not so with the man in the plane he pursued. It was flying crazily, but clinging to one course, nevertheless--into the northeast, towards land, some two hundred and fifty miles over the horizon.
The great silver shape of the ZX-1, barren, now, of life, dropped away, speeding ever due west; the hazy dots and blur of smoke which denoted the motionless Black Fleet vanished. But Chris was in contact with the fleet's flagship once more, through the compact radio-telephone set of his scout. As he flew, his eyes fixed steadily on the plane ahead, he was rapping into the microphone the story of what had happened. He told of the invisibility of the strange marauder, of how accurately he had judged the time of his raids; of how he, Chris, had managed to prevent the destruction of the ZX-1.
"He uses a tremendously expansive gas resembling carbon monoxide," he went on. "It seeps into every cranny of the dirigible, killing everything. The crews got no warning; they didn't know what was happening; couldn't see him! Well, I managed to wound him on the ZX-1. He beat it. I'm following him. If he lasts out, he'll go to where he came from, and we'll find out who's in back of all this. Let you know where his base is soon as I get there. Keep listening. Okay? Right; signing off."
Silence, then, between the scout and the flagship far behind....
* * * * *
On--on Time passed. The scout's gas was down below the half-way mark. They had covered two hundred miles now at a speed just bordering three hundred. The plane ahead looked uncanny with its apparently empty cockpit, but Chris could see all too well that death was pressing at its invisible pilot. The big machine was literally staggering in its course as the hands on its control stick grew weaker; was yawing wildly, even as the ZX-1 had yawed after her crew had been slain by vapors they could not see.
"He's got to last out!" Chris muttered. "Got to!"
At that moment land appeared, and the fleeing plane altered its northeast course to due east with an abrupt jerk.
First it was a mere hazy line on the horizon; then it rose to a thrust of land, jutted with cloud-misted hill-tops. Then, as the two roaring specks that were airplanes came closer, heavy tropical foliage became distinct, and white slashes of surf breaking on the shore. This was the Azuero Peninsula, most western point of the Republic of Panama.
Aside from one small cluster of wretched huts, it was practically uninhabited. Guarded by dense growth, only one or two of the dusty paths which passed for roads wandered aimlessly through its tangled creepers, trees and bush. To the southeast was the broad Gulf of Panama, doorway to the Canal; on the other sides this thumb of land was surrounded by the reaches of the Pacific.
The plane was obviously nearing its eyrie--dropping lower and lower, losing speed and altitude; and also threatening each moment to tumble down out of control into the smothering welter of olive-green below, with a dead, unseen body in its cockpit.
But where was the landing field? They were now over the very heart of the Peninsula, and still Chris, searching through his telescopic sight, could see nothing but the monotonous roll of jungle. They must come to it soon, or be over to the Caribbean Sea and the Mosquito Gulf.
Then suddenly he started forward, staring. Of course there was no landing field in sight. The mystery plane needed none. It possessed the power of the helicopter: it could rise straight up or sink straight down.
From each one of the two knob-like projections on its upper wing that had puzzled him previously, a propeller had risen and unfolded into long, flat blades. They whirled in circles of light in the sun; and the airplane beneath them poised, all but motionless, its main propeller swinging idly, and then began slowly to drop downwards.
But Chris, swooping nearby, was still perplexed. Dropping down to what? There was only the dense tropical growth beneath. He could see no trace of men, no clearing, however small, no base--nothing but the jungle.
"How in the dickens--" he began; and then stopped. At that moment the jungle's secret was revealed.
* * * * *
As the helicopter-plane dropped to within a few hundred feet of it, a strip of the sea verdure split in two and reared up. It looked, at first, like magic. But from aloft Chris saw the trick and how the camouflage was worked. What appeared to be a slice of the jungle roof was, in reality, a metal framework cunningly plastered with layers of green growth. An oblong, some fifty by a hundred feet, it parted in the middle like a bridge that opens to let a steamer through, revealing the lair of the plane.
Soon more was revealed. Two tiny, green-painted huts stood in the minute clearing, and a few white-clad figures were by them, staring up at the plane sinking down and at the other plane which soared above like a buzzing mosquito.
One of the dwarfed figures in white waved an arm. The others around him darted into the left-side hut. Then the helicopter-plane's wheels touched the small space allotted for it in the clearing, and the whirling propellers halted.
"So that's the secret!" Chris muttered. He pulled the microphone of the radio-telephone to his lips and angled with the dials for connection with the fleet hundreds of miles behind, meanwhile noting his exact position on Azuero Peninsula. But before he spoke, some sixth sense bade him glance below once more.
An icy shiver gripped his body.
A thin slit had appeared in the roof of the left-side hut. A spot of bright blue light was winking evilly inside it
. And, though he could not hear it, Chris knew with terrible certainty that a shrill, impatient whining was piercing from the machinery of a weapon inside that hut--a weapon whose fangs had forked close to him once before--a weapon which the winking eye of blue presaged.
It struck. But at the same instant Chris leaped desperately from the cockpit of the scout.
* * * * *
He leaped almost into the teeth of the blue-tinged ray which knifed up with uncanny accuracy from the slit in the roof of the hut. He was conscious of a flash of unearthly light, of terrible heat which came with it. Only the force of his jump saved him. He pulled the ripcord of the 'chute strapped to him and jerked to a pause; then he was swinging beneath a mushroom of white, trembling as he stared at the fate he had missed by a hair's breadth.
A web of spectral blue light had enveloped the abandoned scout. The plane appeared to shudder, hanging almost motionless in the wraith-like mist. Then, with a crackle, the wings and tail shivered into countless fragments; the stripped fuselage nosed over and plunged earthward, a roaring mass of flames. A fiery comet, it screamed past the man who swayed beneath his 'chute, coming within a few hundred feet of him and searing him with its hot breath. Then it drove into the dense flanks of the jungle growth.
Soon only a charred skeleton marked the last landing field of a scout of the dirigible ZX-1.
"And now, I guess," Chris whispered, "they'll turn that ray on me...."
But he had only been a thousand feet up when he jumped. Already he was close to the top of the jungle. The clearing and its huts disappeared from view; he was out of range of the swift-striking ray. And, he reflected, though the scout was gone, he was still free--and could get to the Canal....
But tropical growth is difficult to land in.
A moment later his swinging body crashed through the branches of a tree, and he pitched forward, unable to control the impetus. A sudden shock of pain stabbed through his head and everything spun dizzily before him. He knew he was falling, jerking down as the parachute ripped on the boughs. There was another impact which drove all remaining consciousness from him.
