It blazed into being with no warning, persisted for about a half-second, and died as suddenly.

And on the road, where the great roadster had been, with a man and girl in it, was nothing. A charred black streak 'showed. That was all.

3. SATAN SCHEMES.

In a tower of the Book Hotel, next noon, two men sat talking.

One, thin, of average height, with thin gray hair and eyes lidded by colorless flaps that looked like the membranes veiling the eyes of a bird of prey, was president of the Universal Motors Corporation. Detroit's biggest automobile combine. The other was Ascott Keane, criminologist.

Keane got up from his chair and paced slowly back and forth across the room, his wide-shouldered, athletic body moving with the perfect muscular coordination of a trained athlete. His gray eyes were like chips of ice in his lean face. His black brows were drawn low.

"There is only one person on earth who could possibly be responsible for this," he said.

Corey, president of Universal, stared up at him. His veiled eyes looked more than ever like the eyes of a bird of prey - but of a very frightened bird, now. But even in his fright, he preserved his business caution. So many men, these days, claimed knowledge to which they had no right - and tried to extort money from you on that claim!

"Who is that?" he asked, warily, "Doctor Satan." said Keane, Corey sighed and leaned back in his chair, "You are right, I guess you know the answer behind the - the disappearances, and you claim to. The voice that spoke to me ended the insistence by saying that its owner was somebody with the bizarre name, Doctor Satan."

Keane stared at him. On Keane's face was a trace of impatience. He had read the man's thoughts, and didn't like them. But Corey, wealthy and powerful as he was, was only a p.a.w.n in the game. And one doesn't become annoyed with p.a.w.ns, "Tell me about the voice," he said, * * * *

Corey swallowed with difficulty. His face was greenish. "I was in my office. The office is sound-proofed, so that no voice could have come from outside. I was alone - even my secretary had been sent out and the door was locked. And while I was sitting there - a voice came to my ears, "You have heard the news," the voice said, "You have heard how Charles Besson, and Thomas Dryer, son of Dryer the motor magnate, were consumed in a mysterious violet flame,"

Corey looked at Keane like a terrified child, "It was almost like the voice of a second self speaking! It came so un.o.btrusively and - and naturally - that for a minute I wasn't startled at all. But then - I was. I realised that there wasn't a soul but myself in that locked, sound-proof room. A voice - save mine - couldn't sound in there! But this one did; a soft, almost gentle voice, but it gave me chills. It went on: "You are thinking of that news now. You are planning how best to take advantage, in a business way, of the fact that Besson has died suddenly, and that Dryer is stunned and helpless from the blow of his son's death.

"That - that was true," Corey blurted out, "It was as if someone was reading my mind..."

"Well, I was thinking about the business advantages that might accrue to Universal by the tragedies. Any man would," Corey shivered, "The voice said..."

"You have more important things to think about now. One is - your own life. Another is how you can arrange your financial affairs so that you take ten million dollars in cash from your fortune. For that is the price of your life. Ten million dollars. You will deliver it to my servant within the next few days, or you will die as Besson and Dryer died, I swear that, and Doctor Satan has never broken a vow."

Corey glared at the back of his bony, prehensile hand, "Those aren't the exact words, but that's the message given by the voice. And that was the name: Doctor Satan. I'd have said the whole thing was some clever trick, played by a master of hypnotism or ventriloquism to cheat me out of money, I'd have defied the orders of the voice, of course - if it hadn't been for the awful way in which Besson and Dryer's son died. My G.o.d, can anyone really do that - consume people in violet flame - at will?"

Keane shrugged, "According to the newspaper and many witnesses, someone can. What do you intend to do?

"I don't know. That's what I came here to ask: I had about decided to pay, when you phoned. How did you happen to get in touch with me, anyway, at such a crucial moment?" A bit of the old wariness and business suspicion came back to Corey's face.

Keane smiled, "The moment I read, in New York, of the inexplicable tragedies that had happened here, I flew to Detroit. Both victims had been prominent in motor manufacturing circles, so I began with you, intending to run down the list of executives till I found one who had been threatened. I knew who was behind the crimes, and I know something of how he works, so my course of action was outlined for me. You told me you had been threatened; I asked you to see me - and that's the answer,"

Corey sighed, "Shall I pay this Doctor Satan? Ten million dollars! It's colossal! But life is more important than money..."

"Even if the price asked was only ten cents," snapped Keane, "You shouldn't pay it."

"But he'll kill me! The flame...."

Keane's long jaw squared. His firm mouth became firmer, grimmer. "I've found this man more than once," he said. "I've beaten him before. I'll do it again. Don't pay. Your life will be saved if you take one precaution."

"And that?" said Corey eagerly.

"Don't ride in a car. In fact, don't ride in anything capable of high speed: bus, train, anything." He glanced toward the door, indicating that the interview was over. "If you refrain from that, you'll be all right."

Corey went out. The door opened after his exit, and Keane's secretary came into the room. Tall, lithe, beautiful, with dark blue eyes and hair more red than brown, she stared at her employer with a look in her eyes that would have revealed much to him had he been gazing at her at the moment instead of looking unseeingly out the window at the roof-tops of the automobile city.

Beatrice sighed and came up to him.

"You have found out how the deaths were caused?" she asked, professionally, with the glow hidden in her eyes.

Keane nodded absently. "I have found out several things. Not exactly, in detail, but closely enough to map out my plans.

"Doctor Satan is up to his old methods of harnessing the forces of nature to do his crimes for him. It was nature that killed Besson and Dryer's son. Static electricity.

"Both Besson and young Dryer were notoriously fast drivers. Very well, Doctor Satan contrived a method of generating and storing static electricity in enormous amounts. Probably the generating was done by the wheels themselves, turning at fast speeds. The electricity was stored in some small device that wouldn't be noticed if examination was made of the car before it was taken out. When a voltage was built up that would be far beyond any amount that could be registered on any recording instruments yet devised, it exploded the storage device - and utterly consumed the car and occupants and everything else. That is the only thing that would explain the violet light told of by the witnesses. In a way, a natural death. But in a gruesome, fearful, spectacular death - which was so horrifying and would cow other motor manufacturers that they would give Doctor Satan anything he asked rather than risk the same fate themselves."

"Horrifying and fearful enough," breathed Beatrice with a shiver. "Ascott - you have escaped the other deaths this fiend has invented. Can you escape this? For of course he will turn the new weapon on you, too. More than anything else on earth, he wants to get rid of you. He'll try to kill you as soon as he learns you are here."

Keane laughed a little, without humor. "As soon as he knows I'm here? My dear, you underestimate him. As surely as we live and breathe - he knows that now!"

At twenty minutes past noon a man in the dungarees of the Union Airlines mechanics turned off a sidewalk into the yard of a factory. It was a small factory, two stories high, less than an eighth of a block square. Its windows were boarded up. The yard was grown with weeds.

A man sat in the open doorway of the deserted-looking building. He was an elderly man, poorly dressed. His faded blue eyes stared straight ahead with curious blankness. His face was stubbled with three days growth of beard.

The man in the dungarees came up to the doorway. A small, monkey-like fellow with a mat of hair over his face through which peered small, cruel eyes, he hopped as he walked in an oddly animal way.

"Is anyone in?" asked the watchman.

The watchman's faded blue eyes did not move. They continued to look straight ahead, as he sat there like a statue. "Yes, sir," he said.

"How many?" asked the man in dungarees.

"Two, sir."

The watchman's lips moved like mechanical things. He looked and acted like something actuated with springs and wires.

The little man in dungarees shivered a bit. His pale eyes narrowed with an emotion that might have been fear. He walked past the watchman, who did not move a muscle, and into the factory building.

It was dark in here in spite of the noon daylight outside. The reason was that the entire inside of the first floor was draped closely in heavy black fabric, which also stretched from a frame crossing in front of the door, so that the door could be open innocently and yet outside eyes could not see in and detect the black drapes.

The little man pa.s.sed under the door drape. He entered the dark interior, which was dimly lit by red electric bulbs so that it resembled a corner of some weird inferno.

Over a bench on which was a glistening small receptacle about a third the size of a cigar-box, a figure bent which was like something seen in a fanciful ill.u.s.tration of h.e.l.l: a tall, gaunt figure draped from head to heels in a red robe, with red gloves shielding the hands, and a red mask of the figure, red had been draped, a skull-cap, from which protruded two Luciferian horns in imitation of the horns of the Devil.

Next to this eerie figure was the body of a legless man - gigantic torso supported by calloused, powerful hands.

"Girse," said the imperious, red-draped figure, without turning its head.

The little man in dungarees drew a quick breath. The red figure had its back toward him. It could not have heard his soft entrance. Yet, as though it had been facing him, that entry had been noted.

"Yes, Doctor Satan," he said, "Report, please."

Girse hopped closer in his monkey-like fashion, and stood next to Bostiff, the legless giant. From under the voluminous dungarees he drew a flat leather case.

"Miller, the truck manufacturer, did as you ordered," he said facilely to Doctor Satan. "Here are thirty checks, of one hundred thousand dollars apiece."

Doctor Satan's coal-black eyes glowed from the eyeholes of the red mask. In them was glacial triumph.

"It is well. You got into the Union Airlines hangar?"

"I did," said Girse, his pale eyes glinting.

"You attached the storage cube?"

"I did, with the wire leading to the propeller, and with fins attached to the propeller blades."

Unholy satisfaction glittered in the coal-black eyes. Then it was dimmed, and the light of rage glowed there.

"It will be as we wish it - unless Keane discovers it in time."

"Keane - is here?" quavered Girse.

Bostiff spat out an oath, his dull eyes red with fury.

"He is here," replied Doctor Satan. "I gleaned that from the mind of Corey. He is here, in Detroit. And Corey has seen him and was advised not to meet my demands. That was foreseen - which is why you attached the storage cube to the propeller. He is in a tower suite at the Book Hotel, with his secretary Beatrice Dale. And he is daring to match his wits against mine once more."

Icy murder flared in the coal-black eyes. The red-gloved hands closed slowly, quiveringly.

"This time, Ascott Keane dies! This time, I will get rid of the one obstacle between me and unlimited power, through fear, over the minds of men."

He turned back to the bench, with his red-gloved fingers delicately adjusting tiny, fine plates of some substance like mica which packed the interior of the small metal container on which he was working - a container like that which had been attached to the sedan of Besson and the roadster of young Tom Dryer.

"With Keane out of the way," he was saying, "I could be supreme on earth -and I will be!"

4. THE VOICE OF SATAN.

The late evening papers gave the news of Doctor Satan's latest blow against the ancient law: Thou shalt not kill. Beatrice Dale brought the paper in to Keane. He was about to go out, and she handed it to him without a word.

This afternoon, at four o'clock, Mr. H.C. Corey, president of Universal Motors, was killed in an airplane accident twenty miles out of the Detroit landing field.

Mr. Corey, called on urgent business to New York City, chartered the plane for himself alone and took off at three-forty. The plane circled the field once, then headed east. Twenty miles from the field, it exploded.

Union Airline officials have no explanation to make. The explosion, according to eye-witnesses, was accompanied by a violet flame, which is not the type of flame resulting from gasoline explosions......

Keane read the account, then crumpled the paper in a grim hand.

"Corey dies in unique plane accident," the item was headed. And across half the front page was spread the account: * * * *

Keane drew a deep breath. "Called on urgent business to New York City," he quoted. "The fool! He committed suicide. Doctor Satan gave orders. I told him not to ride in anything capable of speed."

He went toward the door. "I'm going to Besson's home." he said to Beatrice. "I want to talk with Besson's chauffeur about the sedan the man was killed in. I'll be back in an hour."

Carlisle, Besson's chauffeur, but his lips as he faced Keane in the cool dimness of the great garage.

"I suppose I should have gone to the police about it," he was saying unsteadily. "But I couldn't see what good that would do then, and I knew I'd get in a lot of trouble over it."

"You're sure it was Besson?"

"No, later I realized I couldn't be sure," Carlisle admitted. "I heard his voice, and I'll swear it was his voice. And I saw his back, and he was wearing a checked suit as he usually does. But I'll have to confess I didn't see his face."

"Girse," murmured Keane. "Made up as Besson - with Satan himself speaking in Besson's voice from a distance...

"What?" said Carlisle.

"Nothing, go on."

"That's about all. The man I thought was Mr. Besson went out, with a bag and everything as if on the Cleveland trip, and then came back in about half an hour. I didn't see him return - I only heard the car drive in and went down and found the sedan. The first I knew something was wrong was when Besson called, half an hour later, asking if the sedan was ready for his trip! I thought he'd gone crazy, then."

"You have no idea where the Man was driven in that half-hour?" said Keane.

"None at all," said Carlisle. "And now, of course, no one will ever know. Because there isn't any sedan to look over any more."

Keane's lips compressed. "There's no sedan, but I think we can find out where it went in that fatal half-hour. Have you cleaned out in here recently?"

Carlisle looked at the floor of the garage and shook his head. "We haven't kept up quite the schedule we usually do since the boss - died. The garage floor hasn't been swept...."

"Good," said Keane. "Where did the sedan stand in here?"

Carlisle indicated the pace nearest the end wall. Keane went there, bending low, critically examining the concrete. "The man drove it back into this spot before Besson took it out?"

Carlisle nodded. Keane got to his knees. There were slight flakes of dust and dirt from a car's tires on the floor. Keane took up some of these and put them carefully about an envelope. He turned to go.

"Shall I tell the cops about this?" said Carlisle, white-faced.

Keane shook his head. "It would get you in a lot of trouble, as you said. And I don't think it would do any good. You can't be blamed for being fooled by a man who killed your employer."

He went out, with the chauffeur's thankful and admiring gaze following him.

At the curb before the Besson home was the coupe Keane had hired to get about the city in. He got in behind the wheel and headed for the near-down-town section.

He was on his way to the laboratory of a friend of his. In New York he had his own laboratory, vastly better than the one owned by his friend: but he hadn't time to send to New York and he thought the friend's equipment would be sufficient enough to perform the task he wanted.

As a man will do sometimes, Keane broke his own strict rule - disregarding the very warning he had given Corey: not to ride in anything capable of speed.