Bittman smiled. "I see through your ruse to get me out of harm’s way. But, of course, I will call the officers."

He retreated down the wide stairway.

Doc continued to follow the wire. It terminated at a door of a front apartment.

Hardly had he determined that fact when a storm of bullets crashed through the door.

ONLY Doc’s instinct for caution, which had urged him to keep clear of the door, saved his life.

"They’re inside!" Monk howled. "Now for a rat killin’!"

Monk’s compact machine gun coughed a blatting roar of sound. He literally cut the door off its hinges. It fell inward.

More lead came out of the apartment of the besieged. The slugs hit nobody. But they gouged plaster off the walls. The plaster dust became a blinding cloud. A machine gun equipped with a silencer was doing most of the shooting from within the apartment.

"That sounds like Kar’s typewriter!" Monk bellowed. "He’s in there!"

Doc abruptly backed from the door.

"You handle this end!" he directed.

He glided down the stairs to the foyer.

Oliver Wording Bittman stood in a telephone booth, speaking rapidly into the instrument.

"Yes! Send a riot squad!" he was saying.

Doc’s bronze form slid outside. Excitement had gripped the street. A cop was coming from the corner, tweedling vigorously on his whistle. Upon the thoroughfare, the shots within the apartment building sounded like clamoring thunder.

To the apartment window, Doc’s golden eyes flashed. What they saw was about the most disappointing thing possible.

A rope made of knotted bedclothing dangled from the open window! This makeshift cord hung to within ten feet of the walk.

Doc’s gaze raked right and left. They ranged far up and down Riverside Drive. Nowhere did they detect trace of any one who might have escaped down that rope.

Running lightly and leaping, Doc grasped the rope end. Powerful fingers clamped an ornamental fresco and helped the bedclothing support his weight. He went up rapidly.

An ugly face poked out of the window. A pipestem arm brought an automatic pistol into view. But before the weapon had a chance to discharge, an incredible vise of bronze fingers clamped the killer’s scrawny neck. They jerked.

The man came out of the window with a snap. Screeching, he fell to his death far out in the street.

An instant later, Monk, Long Tom and Ham charged the room. Their compact guns stuttered briefly. Two of Kar’s men collapsed. They had been among those assembled by Squint. One fell and leaked crimson over the muffled machine gun which had been used by Kar at the pirate ship, Jolly Roger.

Of Kar, there was no sign.

"He got away — down the rope of bedclothing," Ham declared regretfully. "Although it is possible he was never in the room!"

A brief examination showed the secret phone line terminated in the apartment of death. Glancing from the window, Doc also ascertained another thing.

"You can see the Jolly Rogerfrom here," he informed Monk. "That accounts for Kar’s appearance. He saw us capture those men of his from the underwater tank."

DOC returned with his friends to his skyscraper office downtown.

The police received from Doc Savage an account of what was happening. Doc, however, withheld all reference to the plan to steal the gold destined for the Chicago banks.

This puzzled Ham.

"We’ll stop that robbery ourselves," Doc explained. "Kar will use his infernal Smoke of Eternity. The police have no defense against it. Many of them would be killed."

"Well, won’t Kar use it on us, too?" Monk snorted.

"If he applies it to you, I want to be watching!" the sharp-tongued Ham told Monk. "I’ll bet the cloud of smoke it turns you into will have a spike tail, horns and pitchfork!"

"Maybe. But it won’t make a noise like this!" And Monk gave a boisterous imitation of a pig grunting.

Ham reddened and shut up. All Monk had to do to get Ham’s goat was make some reference to a porker. Monk often made those piggy, grunting noises just to see Ham swell up with rage.

Long Tom suddenly emitted a howl of surprise. Wandering about the office nervously, he had chanced to look behind the safe.

A large hole gaped there! The solid steel had simply been wiped away!

Doc hurriedly opened the safe.

The rock specimens from Thunder Island were gone!

"Kar, or one of his men, opened a hole in the rear of the safe with that Smoke of Eternity, and got the specimens!" Doc declared.

"But how did he know they were there?" Monk muttered.

It was Oliver Wording Bittman who suggested an answer. He indicated the spire of a skyscraper some blocks distant. From an observation tower which topped this, it was possible to see into Doc’s office.

"They must have had a man watching from there!" he offered.

Doc drew the shades, saying, "It won’t happen again."

"Doc, that shows you were on the right trail with those specimens," Johnny, the geologist, spoke up excitedly. He adjusted his glasses which had the magnifying lens on the left side. "Otherwise, Kar would not have taken so much trouble to take them away."

Night had fallen. In the great buildings surrounding Doc’s high perch, only a few glowing freckles marked lighted windows.

The police commissioner of the City of New York paid Doc Savage’s office a call in person to express his appreciation for Doc’s services thus far in wiping out the fiendish Kar and his gang. Shortly after this, Doc received a telegram, also expressing thanks, from the New Jersey police official in whose jurisdiction the murder of Jerome Coffern had occurred.

And the tabloid newspapers ranted at the cops for not telling their reporters what was happening. The police were keeping secret Doc’s connection with the sudden epidemic of death among criminals, at his request.

Doc now locked himself in his laboratory. He retrieved from the bottom of the microscope, where he had hidden it, the tiny capsule which had held the Smoke of Eternity. With all the resources of his great laboratory and his trained brain, he set to work to learn the nature of the strange metal.

It was nearly midnight when he came out of the laboratory.

"You fellows stick here," he told Monk, Ham, Renny, Johnny, Long Tom and Oliver Wording Bittman.

He departed without telling the six men whence he was bound or what nature of plan his profound mind had evolved.

Chapter 11. DOC SPRINGS A TRAP

THREE o’clock in the morning!

A black ghost of a night seemed to have sucked the city into its maw. There was fog, like the clammy breath of that night ghost. Out on the bay, a night-owl ferry to Staten Island hooted disconsolately at some fancied obstruction in its path.

The financial district was quiet. The silence in Wall Street was like that among the tombstones in Trinity Churchyard, which lies at the uphill end of the street.

The big feet of occasional policemen made dull clappings on the deserted sidewalks. Periodic subway trains rumbled like monstrous sleepy beasts underground.

Things more sinister were impending around the bank, the vaults of which held the gold coin that tomorrow was to go to the aid of hard-pressed Chicago financial institutions.

The watchman didn’t know it, as yet. He was a thick-headed chap, honest, but inclined to do things suddenly and think about it later.

"When I see somethin’ suspicious, I shoot and ask questions afterward," he was wont to say. He was proud of this. So far, it had miraculously failed to get him into serious trouble. The only people he had shot were those who happened to need it.

The watchman noted a strange grayish haze which seemed to hang in the bank. He passed this off as fog. He would have thought differently, had he seen an enormous hole which gaped in one wall of the building. But he failed to see this, because most of his attention went to the doors and windows, where crooks usually tried to enter.