Three men had their guns at his great head. But one of the others — he of the battered felt hat who had played the part of a track foreman so smoothly in the afternoon — raised his hand.
“No! Hold the slugs,” he said thoughtfully. “What we want is information. We were going to get it out of the babe. But she may be too stubborn to talk, no matter what we do. This guy, though, might crack after he watches us work her over. Anyhow, it doubles our chances. So tie him up with everything in the place, and let him live.”
The man shook his head wonderingly.
“I don’t see yet how he and the other two got off that train in time! They sure die hard.”
The prone giant and the limp, doll-like figure of Nellie Gray were carried to the back of the ferry. Smitty was bound with cable till he looked like a mummy. And the girl, in memory of her amazingly effective struggle, was tied with more precaution than the gang would have given to most men.
The leader of the murderous crew looked toward the lake end of the big hull.
“Open the other door,” he said. “They’ll be coming back soon.”
One of the men, with a great welt on the right side of his face where Smitty’s left fist had brushed him, started the diesel generator. Lights glowed out in the ferry’s cavernous hull. And there was a hum as a small motor swung back the other hangar door.
With the entire end of the barge open, anything short of an overseas clipper could glide within. But no one on shore could see that opening. And no one on shore could see the unexpected spectacle of electric lights illuminating the abandoned hull. There were no cracks in the sound old timbers wide enough for that.
With death in his eyes, the leader of the band turned to the bound pair, to slap the girl out of her unconsciousness and make her talk.
CHAPTER X
The Flying Dutchman!
The weird noise in the sky over Chicago had completely disappeared in the thunder of the Fort Sheridan army planes when Benson and Mac got their big two-motored job off the lake. It was a full ten minutes after the fall of the skyscraper. But Benson wasn’t discouraged by these things.
In the plane was the latest thing in small sound-detectors, with amplifying tubes and a cone-shaped restrictor that could listen to one piece after another of the empty sky and meanwhile keep out all other sounds from other parts of the heavens.
Benson turned this on now and knew he had a listening device almost equal to the army’s great four-horned detectors. He began pointing it in one segment of the sky after the other, trying to pick up the weird noise again.
The army ships left him respectfully alone. A radio call to Fort Sheridan had been relayed to the service planes explaining Benson’s standing and ordering that his ship be given a working berth.
MacMurdie, bleak, blue eyes tense, stared at the pinpoint of drama in downtown Chicago where a big building had once stood.
“The cold-blooded devils!” he grated. “If I ever get a chance at them—”
“You will,” said Benson, shifting the listening ear while his plane slowly circled.
“I hope so, Muster Benson,” said the Scot gloomily. “But ’tis only a thin hope. We haven’t yet any idea of the particular devil directin’ all this.”
“Oh, yes, we have,” said Benson, pale eyes flaring their deadly light. “There are many hints.
“Our man is wealthy. It takes money to hire these underworld rats, and to fix that abandoned barge up in such a complete manner. Our man knows something about the Catawbi Railroad, or he wouldn’t be aware of the existence of the old barge in the first place. Our man knew the Gant brothers quite well, or he’d never have suspected that they were working on the inventions he murdered them to get and keep secret. Our man has some interest in publicizing the destruction of buildings, or he wouldn’t have sent an agent to tell a news reporter all about it in advance.”
He adjusted the delicate listening device again, his white, paralyzed face as expressionless as the face of death, itself.
“We shall start with the friends of the Gants. When we find one who also is rich, is familiar with the workings of the Catawbi Railroad, and has a motive for advertising the destruction of buildings, we’ll be getting warm.”
Mac’s bleak eyes narrowed pessimistically.
“But if we do find him, how will we ever prove any-thin’ on the mon? He’ll be clever as Satan himself. Too smart to leave any clues that a court of law could use.”
Benson said quietly: “Most of the men we fight are as clever as that. But they somehow pay in the end, don’t they? This man will be taken care of — when we discover him—”
Suddenly the plane banked and began racing east and a little north at five miles a minute.
“Ye’ve hearrrd somethin’?” blurred Mac. “The noise?”
“I think so. Listen!”
Benson passed the earphones to Mac, who used both of them. Benson had only pressed one to his head, listening to Mac with the other. Even so, the Scot couldn’t hear with two ears what Benson had caught with one. Not for a minute, that is. Then he got it.
“ ’Tis the dronin’ sound, dead ahead,” he said. “Ye’ve hit the direction square on the nose.”
“We’ll hit whatever makes the sound pretty soon, too,” Benson said calmly. “I’ll back this plane against anything else in the sky, normal or supernatural, for speed.”
He opened the throttle wide. The twin motors screamed as they sent the big plane forward at four hundred miles an hour.
East and a little north. Toward the weird sound in the sky. And toward a low-hanging cloud bank on the horizon that hinted at weather on the morrow less clear than the present amber dusk.
“Keep a close watch ahead, Mac,” Benson directed.
The Scotchman nodded. He heard the weird sound increasing in the earphones. Coming from an empty sky! He stared hard ahead, blinked, stared again.
“See anything?” said Benson, whose pale eyes had caught the blink.
“I don’t know,” Mac said slowly. “I thought I did. But maybe it was only spots before the eyes—”
“Or a man walking fast in the sky,” suggested Benson.
“Now, Muster Benson! How could a mon walk—” Mac broke off sharply. “There is somethin’ ahead. Two little dots, close together, goin’ about as fast as we are, right for the cloud bank.”
He pressed the earphones to his head.
“The noise has changed,” he said. “It was a drone. Now it’s a kind of whistlin’. Like somethin’ big and alive might make if it was flyin’ along in misery—Chief! Look! A ghost ship!”
Mac’s cry was unnecessary. Benson’s telescopic eyes had caught the bizarre sight before the Scot’s had.
At the fringe of the cloud bank, several miles ahead of them, the ghostly outlines of a plane were slowly appearing in empty air. But it was a plane, it seemed, that was made of fog — or was materializing from a world of dead planes and dead pilots.
Thin and gray, like the cloud-stuff itself, the thing briefly showed at the edge of the mist. A ghost plane! A Flying Dutchman of the air. Then it slid into the cloud bank, mist returning to mist, and disappeared from view.
The whistling noise disappeared from the earphones, too. The drone had faded into the eerie whistling; now that had faded into nothingness. The sky was empty of sound save for the background noise of their own motors.
“It’s gone!” exclaimed MacMurdie, freckled face screwed up. “If ye could say a thing has gone when it was never properly here in the first place. Because, d’ye see, a ghost isn’t really here to begin with—”
Benson said nothing. He was hurtling the ship toward the point where the thin and wavering outlines of the ghost plane had last been seen. He passed it in about ten seconds, and entered the clinging cloud bank.