through a door. He slammed it. Ham pitched against the panel. It resisted.
Seizing a chair, Ham battered the door down. He ran across a dining room, then a kitchen. A rear door gaped open beyond. It let him into an alleylike court. There was only one exit from this, a yawning space between two buildings, to the right.
An indistinct, rapidly moving figure dived into this opening.
Ham pursued. He pitched headlong between the buildings, came out on the walk, and saw his quarry scuttle under a street lamp at the corner.
Ham set out after him-only to bring up sharp as a powerful voice came to him from a near-by door recess.
'I'll follow him, Ham!' the voice said.
It was Doc Savage.
Ham understood, then, why Doc had directed, in the message on the skyscraper window, that the ransom-demanding courier was not to be followed. Doc intended to do the trailing, hoping to be led to the master mind who was behind all this callous, inhuman bloodletting.
In order not to make the fleeing Oriental suspicious, Ham continued his chase. But at the first corner, he deliberately took the wrong turn.
When he came back, there was no sign of Doc or the half-caste Mongol.
Chapter 6
THE STOLEN GLASS
AT the precise moment Ham was wondering about them, Doc and Liang-Sun were five blocks distant. Liang-Sun was just climbing the steps of a Third Avenue elevated station.
The Mongol had lived much of his life in violence, and knew enough to watch his back trail. He saw nothing suspicious. He kept wary eyes on the stairway until a train came
in. Even after he boarded the almost deserted train, he watched the platform he had just quitted, as well as the one on the other side of the tracks. He saw no one — not a single other passenger got aboard.
He should have watched the rear platform. Doc was already ensconced there. He had climbed a pillar of the elevated a short distance above the station and run down the tracks.
The train clanked away southward, disgorging a few passengers at each stop.
At Chatham Square, very close to Chinatown, Liang-Sun alighted. To make sure no one got off the train after him who seemed in the least suspicious, he waited on the platform until the cars pulled out. Greatly relieved, he finally descended.
Doc Savage, having slid down a pillar of the elevated, was waiting for him, seated in some one's parked car.
Liang-Sun walked rapidly toward the Oriental section. He passed two sidewalk peddlers who, even at this late hour, were offering for sale filthy trays of melon seeds and other celestial dainties.
A moment later, Doc Savage also sauntered past the peddlers.
Both venders of melon seeds and dainties shoved their trays of merchandise in the handiest waste can and followed Doc. Their hands, folded across their stomachs, fingered large knives in their sleeves. Their faces, the color of old straw, were determined.
Doc did not look back. Several times, he glanced down at his hands swinging at his sides. In the palm of each hand was a small mirror.
The mirror showed him the two who haunted his trail.
Doc's bronze features held no feeling as he watched. This master of the Mongols was clever in having men follow Liang-Sun to see that no one dogged his tracks.
Gone were any hopes Doc had of locating the master mind through Liang-Sun — unless he could be induced to talk by force.
Doc's left hand wandered casually into his pocket, drew out four of the glass balls filled with anaesthetic. Holding his breath, Doc dropped them. They shattered, releasing the colorless, odorless vapor.
Doc strode on.
Behind him, the two peddlers walked into the anaesthetic. They fell forward on their faces, nearly together.
LIANG-SUN chanced to turn around at this moment. He saw Doc, saw what had happened. His piping yell of fright sounded like a rat squeal in the dingy Chinatown street. He fled.
A bronze blur of speed, Doc raced after him.
Liang-Sun was fumbling inside the waistband of his trousers. He brought out his sword. Evidently he carried it in a sheath strapped next to his leg.
Doc overhauled him rapidly. The Mongol was only a hundred feet away — seventy-five — fifty.
Then a big policeman, attracted by Liang-Sun's yell of fear, popped around a corner. He stood directly in Liang-Sun's path, revolver in hand.
The Mongol was desperate. He slashed his sword at the cop and the cop shot him, killing him instantly.
The policeman had acted instinctively in defense of his life. He watched Doc come up.
'Sure, an' this is the first man I ever killed. I hope he needed it,' the cop spoke.
He eyed Doc suspiciously. He did not know the bronze giant.
'Was ye chasin' this bird?' he demanded.
'I was,' Doc admitted. 'And don't let the fact that you killed him bother you. He is a murderer, probably several times over. He killed a man at the home of Scott S. Osborn to-night. And I think he must have committed other crimes at the residence of Scott S. Osborn's brother not very many minutes ago.'
Doc did not know what had happened in the dwelling of Scott S.. Osborn's brother. But the fact that Ham had chased Liang-Sun out showed something had gone wrong.
The cop was suspicious of Doc.
'Yez jest stick around here, me b'y!' he directed. 'We'll want to ask yez a lot av questions.'
Doc shrugged.
The officer slapped big hands over Doc's person in search of a gun. The fact that he did that was unfortunate. He broke one of the anaesthetic balls in Doc's pockets.
A minute afterward, he was stretched on his back on the walk, snoring loudly.
Doc left the cop where he lay. The fellow would revive after a time, none the worse for his slumber.
From a near-by call box, Doc turned in an alarm to the police station. He did not give his name.
He hurried back to get the two peddlers who had been following him. They should be asleep on the walk.
But they weren't! Some denizen of Chinatown had moved them. Doc knew it must have been the work of some of the Mongol horde.
Chinatown, despite all the fiction written about it, was actually one of the quietest sections in the city. No legitimate resident of the district would court trouble by assisting the unconscious pair.
A brief, but intensive search disclosed no sign of the vanished two.
HALF an hour later, Doc was in his skyscraper office uptown. None of his five men had returned.
With a chemical concoction from the laboratory, Doc erased the invisible writing off the window. Then he inscribed a fresh message there.
Swinging out into the corridor, he rode the button until an elevator came up. The cage doors opened noiselessly, let him in, and closed. There was a windy sigh of a sound as the lift sank.
Adjoining Doc's office was a suite which had been empty some months. Rents were high up here in the clouds, and times were tough, so many of the more costly offices were without tenants.
It would have taken a close examination to show the door of this adjoining suite had been forced
