The Invisible Cloak's Threat

Leaving the Pennsylvania mills the aeroflyer, traveling at high speed landed the party within a very short time on one of the tall landing buildings in New York. Ralph and Alice made their way down to the elevated roadway, where, at Ralph's suggestion they put on their power skates, for, as he explained smilingly, it was but a short distance to his home and the exercise would do them both good and give them an appetite for luncheon.

After leaving the Pennsylvania mills, the aeroflyer traveled at high speed. It soon landed the party on one of New York’s tall landing buildings. Ralph and Alice went down to the elevated roadway. There, at Ralph’s suggestion, they put on their power skates. Smiling, he explained that his home was only a short distance away. The exercise would do them both good and give them an appetite for lunch.

When they were but a little way from their destination Ralph became conscious of a faint hissing sound close behind them. Twice he glanced over his shoulder, but the roadway at that hour—it was just before noon—was deserted.

When they were close to their destination, Ralph heard a faint hissing sound just behind them. He glanced over his shoulder twice, but the road was deserted. It was just before noon.

Yet the sibilant sound persisted, seeming to be getting closer and closer, like some persevering insect about to alight.

Yet the hissing sound continued, seeming to get closer and closer, like a persistent insect about to land.

Alice apparently heard nothing, or perhaps she thought it merely one of the noises of the street, for she chattered on in the gay animated fashion that was one of her charms, oblivious to the fact that the man at her side was so preoccupied that he scarcely replied to her.

Alice apparently heard nothing, or perhaps she thought it was just another street noise. She kept chatting in the cheerful, lively way that was one of her charms. She did not notice that the man beside her was so distracted that he barely replied.

For Ralph had now satisfied himself that there was nothing anywhere around them which could cause that untiring pursuant hiss. Then from what secret invisible source did it emanate—and why?

Ralph was now sure that nothing around them could be causing the relentless, pursuing hiss. So where was it coming from, and why?

To the scientist, accustomed to explaining the unexplainable, it was ominous—menacing—

To the scientist, who was used to explaining the unexplainable, it was ominous, threatening.

Again he turned to look behind him, along the deserted way, and at that moment he heard a stifled cry from the girl beside him. He whirled to face her, and faced—nothing! He was alone in the empty street!

Again he looked back along the deserted street. At that moment, he heard a muffled cry from the girl beside him. He spun around to face her, but she was gone! He was alone in the empty street!

Unbelieving, doubting the evidence of his eyes, he stared about him, too astounded for the moment, by this mystifying and amazing disappearance to think collectively.

Unable to believe his eyes, he stared around him. The mysterious and astonishing disappearance had left him momentarily too stunned to think clearly.

Above him the sun shone in a clear blue sky, before and behind him stretched the still roadway. Then he was aware of the silence, the deadly quiet. For the hissing had receded into nothingness, and with it, Alice.

Above him, the sun shone in a clear blue sky. The still roadway stretched before and behind him. Then he noticed the silence, the deadly quiet. The hissing had faded away, and with it, Alice.

As the full force of the catastrophe struck him, something akin to panic seized him. Danger to himself he could have faced with the calm courage of a brave man, but this unseen and unexpected blow from an invisible source aimed at the girl so close and dear to his heart smote him with a chill terror that for an instant held him powerless in its grip.

As the full force of the disaster hit him, he felt something like panic. He could have faced danger to himself with the calm courage of a brave man. But this unseen, unexpected blow from an invisible source was aimed at the girl so close and dear to his heart. It filled him with a cold terror that left him powerless for a moment.

That he should have been careless when she was in danger—but this was no time for self-reproaches. To act, and to act at once—that was vital.

How could he have been careless when she was in danger? But there was no time to blame himself. He had to act, and act at once.

Thoughts of high frequency radio waves—of X-rays—of Fernand—

Thoughts of high-frequency radio waves, of X-rays, of Fernand...

"Fernand!" he exclaimed aloud, and with the name coherent thought returned. Putting on all possible speed he covered the distance to his home in a few seconds and dashed up to his laboratory, the while his swiftly-working brain attacked the greatest personal problem that it had ever been called upon to solve.

"Fernand!" he exclaimed, and with the name, clear thought returned. At full speed, he reached his home in a few seconds and rushed up to his laboratory. All the while, his quick mind worked on the greatest personal problem he had ever faced.

Having experimented with ultra-short waves, he knew that it was possible to create total transparency of any object if the object could be made to vibrate approximately at the same rate as light. He was familiar with the theory, and although he had worked on it at times, he had never seen a practical demonstration of it.⁷ He realized a machine was in the hands of someone, intent on kidnapping Alice. He knew, too, that a police description would be flashed within a radius of thousands of miles instantly, it would be necessary for the abductor to keep Alice invisible for some time to come, for fear of some one seeing and recognizing her. All this flashed through his mind as he assembled a detecting apparatus consisting of a portable aerial and a small box containing a few radio instruments and a pair of headphones.

He had experimented with ultra-short waves. He knew that any object could be made completely transparent if it could vibrate at approximately the same rate as light. He was familiar with the theory and had worked on it at times, but he had never seen it demonstrated in practice.⁷ He realized that someone had such a machine and intended to kidnap Alice. He also knew that a police description would instantly be flashed over a radius of thousands of miles. The abductor would therefore have to keep Alice invisible for some time, to prevent anyone from seeing and recognizing her. All this flashed through his mind as he assembled a detecting apparatus. It consisted of a portable aerial, a small box containing a few radio instruments, and a pair of headphones.

The aerial, by being rotated, could determine the point from which the waves emanated. In ten minutes Ralph had the apparatus rigged up and began rotating the aerial, until a roaring noise was heard in the telephones. He knew that this must be the apparatus producing the invisibility, and within a few seconds he had dashed from the house on his power skates, carrying the detector in front of him. Two of his assistants accompanied him.

By rotating the antenna, Ralph could determine where the waves came from. In ten minutes, he had the equipment set up. He began turning the antenna until he heard a roaring noise in the headphones. He knew it must be coming from the device producing the invisibility. Within seconds, he dashed out of the house on his power skates, carrying the detector in front of him. Two of his assistants went with him.

The pursuit was on. As they approached the kidnapper the sounds in the telephones became stronger. They sped along Broadway, while the hastily notified police kept the way open. The rising sound in the 'phones clearly indicated they were headed directly toward the abductor.

The chase was on. As they got closer to the kidnapper, the sounds in the telephones grew louder. They sped along Broadway while the police, alerted in a hurry, kept the way clear. The growing sound in the phones clearly showed that they were heading straight toward the kidnapper.

They gained steadily on him while the rolling, flying police cleared Ralph's way with their shrieking sirens, while the kidnapper had to pick his way slowly through crowds.

They steadily gained on him as police on the ground and in the air cleared Ralph's way with shrieking sirens. Meanwhile, the kidnapper had to move slowly through the crowds.

The chase led them into a narrow street on the outskirts of the city.

The chase led them into a narrow street on the edge of the city.

The sound that came through the telephones was now exceedingly loud, indicating that the quarry was near by. But this very nearness was confusing to Ralph, for the volume of sound prevented him from exactly locating the invisible kidnapper and the girl. In vain he turned the aerial in all directions, seeking one point from which it came louder than another that would determine the course of his pursuit. For the moment he was halted, and, like some hound baffled by the cunning of the fox, he cast about him eagerly, waiting for what he knew must come, the next move of the pursued man.

The sound coming through the headphones was now extremely loud, indicating that the quarry was nearby. But this very closeness confused Ralph. The sound was so loud that he could not locate the invisible kidnapper and the girl exactly. He turned the aerial in every direction, trying to find where the sound was loudest. That would tell him which way to pursue them, but he had no luck. For the moment, he had to stop. Like a hound baffled by a cunning fox, he searched eagerly, waiting for what he knew must come: the pursued man’s next move.

And then it came—a deepening tone in the telephones, a gradation of sound that to the trained ear of the scientist told him all that he wished to know. With an exultant cry he sprang forward, and dashed through the entrance of a small store.

Then it came. The tone in the telephones grew deeper, and the change told the scientist’s trained ear all he wanted to know. With a triumphant cry, he leaped forward and dashed into a small store.

The proprietor, whose state of mind may best be described by the word "flabbergasted," struggled for some moments in vain for speech while Ralph and his men, with outstretched hands eagerly swept from wall to wall.

The proprietor was "flabbergasted" and struggled for several moments to speak, but no words came. Meanwhile, Ralph and his men eagerly swept from wall to wall, their hands outstretched.

"Here, here, you fellows," he finally managed to gasp, "what are you after? What are you trying to do? You'll knock something over in a minute. Hey, look out there—there it goes!"

"Hey, hey, you guys," he finally managed to gasp, "what are you after? What are you trying to do? You'll knock something over in a minute. Hey, watch out! There it goes!"

For Ralph had reached around a tailor's dummy, knocking it over as his hands closed upon something behind it, something invisible and yet warm and firm; something that quivered and shrunk away at his touch.

Ralph had reached around a tailor's dummy and knocked it over as his hands grasped something behind it. It was invisible, yet warm and firm. It trembled and shrank away from his touch.

The proprietor, rushing forward to pick up the dummy, stopped short, gaping. Ralph's hands, at the moment of contact, vanished into thin air. But in an instant they re-appeared, as he drew towards him, out of the influence of the ultra-short waves what he knew must be the bound and gagged form of Alice.

The proprietor rushed forward to pick up the dummy, but stopped short and stared. The moment Ralph’s hands touched it, they vanished into thin air. But they reappeared almost instantly. He was pulling what he knew must be Alice’s bound and gagged body toward him, out of the ultra-short waves’ influence.

Once away from the influence of the apparatus she became visible again. A sack had been tied over her head and shoulders and her hands were tightly bound to her sides. She was still on her roller skates, and her feet had been left free, the sack being sufficient to render her almost wholly helpless, and unable to make any effective resistance.

Once she was away from the apparatus, she became visible again. A sack had been tied over her head and shoulders, and her hands were tightly bound to her sides. She was still on her roller skates, and her feet had been left free. The sack alone was enough to make her almost completely helpless and unable to resist effectively.

As Ralph removed the fastenings and released her, she staggered and clung to him, her head dropping in exhaustion.

As Ralph unfastened her restraints and freed her, she staggered and clung to him. Her head drooped with exhaustion.

"Oh," she gasped faintly, "what is it? Where did you go?"

"Oh," she gasped faintly, "what is it? Where did you go?"

"Water!" exclaimed Ralph harshly to those about him, and the fat storekeeper, trembling with excitement, but withal displaying an extraordinary energy for one who could never at any time have been a streamline model, made a dive for a vase of flowers on the counter. Grasping the tops of the flowers with one hand he flung them in a corner, and tendered the vase of discolored water to Ralph, panting the while as one who has run his race, and emerged triumphant.

"Water!" Ralph shouted harshly to those around him. The fat storekeeper trembled with excitement. Yet he showed remarkable energy for someone who could never have been a model of sleekness. He lunged for a vase of flowers on the counter. Grabbing the tops of the flowers with one hand, he flung them into a corner. Then he offered Ralph the vase of discolored water. He panted like a man who had run his race and won.

"I said water—not mud," shouted Ralph in exasperation, as he rubbed the girl's cold hands between his own warm ones.

"I said water, not mud," Ralph shouted in frustration as he rubbed the girl's cold hands between his warm ones.

"Well, that's water, ain't it?" said the man, and Ralph glowered at him.

"Well, that's water, ain't it?" said the man. Ralph glared at him.

"Please," said Alice, trying to withdraw her hands, "I'm all right, indeed I am. I was just a little dizzy for a minute, but it has all passed now."

"Please," Alice said, trying to pull her hands away, "I'm all right, really. I was just a little dizzy for a minute, but it has all passed now."

The color returned to her pale cheeks with a rush, and she straightened herself, and turned away in some confusion, her hands instinctively going to her hair, the gesture that women have ever used when at a loss for words.

Color rushed back to her pale cheeks. She straightened up and turned away, a little embarrassed. Her hands instinctively went to her hair, a gesture women have always used when at a loss for words.

In the meantime, Ralph's two assistants had found the ultra-wave machine by the very simple method of feeling about the spot where the girl had been discovered. When their hands disappeared they knew that they had it, and Ralph ordered some water thrown upon it, which had the twofold result of stopping its activity and of bringing it into view.

Meanwhile, Ralph's two assistants had found the ultra-wave machine by feeling around the spot where the girl had been found. When their hands disappeared, they knew they had found the machine. Ralph ordered them to throw water on it. The water stopped the machine and made it visible.

Having assured himself that Alice was unharmed and recovering from the shock resulting from her misadventure, the scientist made a minute examination of the instrument. It was a complicated machine and one totally strange to him. As he studied it he felt a growing conviction that this was no earth-made machine, but one conceived and made by a Martian. Undoubtedly it was the work of some master of science, a true mental giant.

After making sure Alice was unharmed and recovering from the shock of her ordeal, the scientist examined the instrument closely. It was a complicated machine, and he had never seen anything like it. As he studied it, he grew convinced that it had not been made on Earth, but by a Martian. It was undoubtedly the work of a master of science, a true genius.

Then where, he asked himself, did Fernand—if it was Fernand—secure it, and how? His object, of course, was obvious. He was evidently prepared to go to any lengths to secure the girl for himself. Had he not so threatened her? His method of attack had been ingenious—fiendishly ingenious. Here was no mean antagonist, no petty enemy, but one whose cunning would tax Ralph's resourcefulness to the utmost.

Then he asked himself where Fernand had gotten it, and how, if it was Fernand. His purpose, of course, was obvious. He was clearly willing to do anything to get the girl for himself. Had he not threatened her with as much? His method of attack had been ingenious, fiendishly ingenious. This was no ordinary opponent or petty enemy. His cunning would test Ralph’s resourcefulness to its limits.

When he finally turned away from his inspection he found Alice quite herself again. She was listening to the store proprietor's version of the affair, a story that, under the stimulus of Alice's dark eyes, lost none in the telling, for where facts failed him, imagination did not.

When he finally stopped inspecting, he found that Alice was herself again. She was listening to the store owner's version of what had happened. Inspired by Alice's dark eyes, he told the story in full, using his imagination wherever the facts failed him.

"—flew open before my very eyes," he was saying when Ralph turned around, "as if by unseen hands. And then this terrible sound—I can't scarcely describe it, more like (his eye fell on the ultra-ray apparatus), more like a great machine than anything else. I says to myself, says I, 'There's something strange about this,' I says, 'I'd better be on the lookout, I might be needed, for it looks to me,' I says, 'as though someone was up to something'."

"flew open right before my eyes," he was saying when Ralph turned around, "as if by unseen hands. And then came this terrible sound. I can hardly describe it." His eye fell on the ultra-ray apparatus. "It sounded more like a great machine than anything else. I says to myself, says I, 'There's something strange about this,' I says. 'I'd better be on the lookout. I might be needed, for it looks to me,' I says, 'as though someone was up to something'."

As a matter of fact, he had thought the opening of the door due to a passing wind, and the hissing of the machine, which has already been likened to the buzz of an insect, the humming of a bee, let in by the same agency.

In fact, he thought a passing breeze had opened the door. He also thought the machine's hissing was a bee humming, let in by the same breeze. The machine's sound has already been compared to an insect's buzz.

"And then that black man, he gave me a fright for fair," he went on.

"And then that black man really gave me a fright," he went on.

"What about him? What was he like?" asked Ralph sharply.

"What about him? What was he like?" Ralph asked sharply.

"Ah," said the proprietor, swelling with importance, "that's just what I've been asking myself. Strange we should hit on the same thoughts ain't it?"

"Ah," said the owner, puffing himself up, "that's just what I've been asking myself. Strange that we had the same thought, ain't it?"

"Very," commented the scientist, with wasted irony. "Can't you give any description of him? When and how did you see him, anyway?"

"Very," the scientist said, but his irony was lost. "Can't you describe him at all? When and how did you see him, anyway?"

The proprietor put his hands into his pockets and swayed backward and forward on the balls of his feet. He surveyed each member of his little audience with glances of poignant meaning, as one who had much of consequence to tell—all in good time.

The owner put his hands in his pockets and rocked back and forth on the balls of his feet. He gave each member of his small audience a meaningful look. He seemed to have important things to tell them, but only when he was ready.

Finally he spoke. "He was black," he said, "black all over."

Finally he spoke. "He was black," he said, "black all over."

"Yes, yes," exclaimed Ralph impatiently, "you told us that before. Can't you give us something definite to go by? His face, for instance. What was that like?"

"Yes, yes," Ralph said impatiently. "You told us that before. Can't you give us something definite to go on? His face, for example. What did it look like?"

The other leaned forward and tapped him on the chest impressively.

The other man leaned forward and tapped him on the chest for emphasis.

"Ay, that was black too," he said.

"Yes, that was black too," he said.

"Black!" cried Ralph.

"Black!" Ralph cried.

"Black it was—all covered with a black cloth," said the none-too-intelligent shopkeeper smugly. "He come right out of the air before my very eyes, all black, with a black cloth on his face, and rolled out of my store like a cyclone."

"It was black, all covered with a black cloth," said the rather unintelligent shopkeeper smugly. "He come right out of the air before my very eyes, all black, with a black cloth on his face, and rolled out of my store like a cyclone."

"You should have tried to hold him," said Ralph.

"You should have tried to hold him," said Ralph.

"Well, I gave him a look, I can tell you. He won't forget it in a hurry. I just stood there and looked at him—like this."

"Well, I gave him a look, I can tell you. He won't forget it anytime soon. I just stood there and looked at him, like this."

He screwed up his face in so alarming a manner that one of Ralph's assistants was moved to remark that it was a wonder he didn't drop dead with a face like that.

He twisted his face into such an alarming expression that one of Ralph's assistants said it was a wonder he didn't drop dead with a face like that.

"What d'ye mean?" demanded the owner of the countenance in question.

"What do you mean?" demanded the person whose face was in question.

"I said," repeated the assistant, "it was a wonder he didn't drop dead. I would have. It's all I can do to look at you right now."

"I said," the assistant repeated, "it's a wonder he didn't drop dead. I would have. I can barely look at you right now."

Alice, unable to control her laughter any longer, hastily murmured something about "fresh air" and went to the door.

Alice could no longer stop laughing. She quickly murmured something about "fresh air" and went to the door.

Ralph, keeping his own face straight by a valiant effort, ordered his men to lift the ultra-ray machine and take it back to the laboratory to give it a more minute inspection at his leisure.

Ralph struggled to keep a straight face. He ordered his men to lift the ultra-ray machine and take it back to the laboratory. He would inspect it more closely there at his leisure.

The girl and the man were very silent on their way back to Ralph's home. A tragedy had been narrowly averted and each felt that this first attempt might by no means be the last.

The girl and the man were very quiet on their way back to Ralph's home. A tragedy had been narrowly avoided, and each felt that this first attempt might not be the last.

Only once did Alice voice her fears.

Alice spoke about her fears only once.

"You know," she said, "I am certain it was Fernand." She hesitated for a brief moment and then held out her hand. In the palm lay a small heart-shaped object of a curious translucent green, delicately carved. It was pierced for a chain, and indeed, a part of the chain still hung there, but it had been broken off short, and only a few links remained.

"You know," she said, "I'm certain it was Fernand." She hesitated briefly, then held out her hand. In her palm lay a small, heart-shaped object. It was delicately carved and a curious translucent green. It had a hole for a chain, and part of the chain still hung from it. But the chain had broken off close to the object, leaving only a few links.

"What's that?" asked Ralph.

"What's that?" asked Ralph.

"A charm that Fernand always carries. He showed it to me once. He's very superstitious about it, he told me—and I found it back there in the store when I went to the door."

"A charm that Fernand always carries. He showed it to me once. He told me he's very superstitious about it. I found the charm back there in the store when I went to the door."

Ralph looked very thoughtful.

Ralph looked very thoughtful.

"Then he must have brought that machine from Mars," he said with decision. "And with such resources at his command, I wonder what his next move will be."

"Then he must have brought that machine from Mars," he said firmly. "And with such resources at his disposal, I wonder what he'll do next."