Rising from the writing table in the library, Paul Harley crossed to the mantelpiece and stared long and hungrily at a photograph in a silver frame. So closely did he concentrate upon it that he induced a sort of auto-hypnosis, so that Phil Abingdon seemed to smile at him sadly. Then a shadow appeared to obscure the piquant face. The soft outline changed, subtly; the lips grew more full, became voluptuous; the eyes lengthened and grew languorous. He found himself looking into the face of Ormuz Khan.  
“Damn it!” he muttered, awakened from his trance.
 
He turned aside, conscious of a sudden, unaccountable chill. It might have been caused by the mental picture which he had conjured up, or it might be another of those mysterious warnings of which latterly he had had so many without encountering any positive danger. He stood quite still, listening.
 
Afterward he sometimes recalled that moment, and often enough asked himself what he had expected to hear. It was from this room, on an earlier occasion, that he had heard the ominous movements in the apartment above. To-day he heard nothing.
 
“Benson,” he called, opening the library door. As the man came along the hall: “I have written a note to Mr. Innes, my secretary,” he explained. “There it is, on the table. When the district messenger, for whom you telephoned, arrives, give him the parcel and the note. He is to accept no other receipt than that of Mr. Innes.”
 
“Very good, sir.”
 
Harley took his hat and cane, and Benson opened the front door.
 
“Good day, sir,” said the butler.
 
“Good day, Benson,” called Harley, hurrying out to the waiting cab. “Number 236 South Lambeth Road,” he directed the man.
 
Off moved the taxi, and Harley lay back upon the cushions heaving a long sigh. The irksome period of inaction was ended. The cloud which for a time had dulled his usually keen wits was lifted. He was by no means sure that enlightenment had come in time, but at least he was in hot pursuit of a tangible clue, and he must hope that it would lead him, though tardily, to the heart of this labyrinth which concealed—what?
 
Which concealed something, or someone, known and feared as Fire-Tongue.
 
For the moment he must focus upon establishing, beyond query or doubt, the fact that Sir Charles Abingdon had not died from natural causes. Premonitions, intuitions, beliefs resting upon a foundation of strange dreams—these were helpful to himself, if properly employed, but they were not legal evidence. This first point achieved, the motive of the crime must be sought; and then—the criminal.
 
“One thing at a time,” Harley finally murmured.
 
Turning his head, he glanced back at the traffic in the street behind him. The action was sheerly automatic. He had ceased to expect to detect the presence of any pursuer. Yet he was convinced that his every movement was closely watched. It was uncanny, unnerving, this consciousness of invisible surveillance. Now, as he looked, he started. The invisible had become the visible.
 
His cab was just on the point of turning on to the slope of Vauxhall Bridge. And fifty yards behind, speeding along the Embankment, was a small French car. The features of the driver he had no time to observe. But, peering eagerly through the window, showed the dark face of the passenger. The man’s nationality it was impossible to determine, but the keen, almost savage interest, betrayed by the glittering black eyes, it was equally impossible to mistake.
 
If the following car had turned on to the bridge, Harley, even yet, might have entertained a certain doubt. But, mentally putting himself in the pursuer’s place, he imagined himself detected and knew at once exactly what he should do. Since this hypothetical course was actually pursued by the other, Harley’s belief was confirmed.
 
Craning his neck, he saw the little French car turn abruptly and proceed in the direction of Victoria Station. Instantly he acted.
 
Leaning out of the window he thrust a ten-shilling note into the cabman’s hand. “Slow down, but don’t pull up,” he directed. “I am going to jump out just as you pass that lorry ahead. Ten yards further on stop. Get down and crank your engine, and then proceed slowly over the bridge. I shall not want you again.”
 
“Right-oh, sir,” said the man, grinning broadly. As a result, immediately he was afforded the necessary cover, Harley jumped from the cab. The man reached back and closed the door, proceeding on his leisurely way. Excepting the driver of the lorry, no one witnessed this eccentric performance, and Harley, stepping on to the footpath, quietly joined the stream of pedestrians and strolled slowly along.
 
He presently passed the stationary cab without giving any sign of recognition to the dismounted driver. Then, a minute later, the cab overtook him and was soon lost in the traffic ahead. Even as it disappeared another cab went by rapidly.
 
Leaning forward in order to peer through the front window was the dark-faced man whom he had detected on the Embankment!
 
“Quite correct,” murmured Harley, dryly. “Exactly what I should have done.”
 
The spy, knowing himself discovered, had abandoned his own car in favour of a passing taxicab, and in the latter had taken up the pursuit.
 
Paul Harley lighted a cigarette. Oddly enough, he was aware of a feeling of great relief. In the first place, his sixth sense had been triumphantly vindicated; and, in the second place, his hitherto shadowy enemies, with their seemingly supernatural methods, had been unmasked. At least they were human, almost incredibly clever, but of no more than ordinary flesh and blood.
 
The contest had developed into open warfare. Harley’s accurate knowledge of London had enabled him to locate No. 236 South Lambeth Road without recourse to a guide, and now, walking on past the big gas works and the railway station, he turned under the dark arches and pressed on to where a row of unprepossessing dwellings extended in uniform ugliness from a partly demolished building to a patch of waste ground.
 
That the house was being watched he did not doubt. In fact, he no longer believed subterfuge to be of any avail. He was dealing with dangerously accomplished criminals. How clever they were he had yet to learn; and it was only his keen intuitive which at this juncture enabled him to score a point over his cunning opponents.
 
He walked quite openly up the dilapidated steps to the door of No. 236, and was about to seize the dirty iron knocker when the door opened suddenly and a girl came out. She was dressed neatly and wore a pseudo fashionable hat from which a heavy figured veil depended so as almost to hide her features. She was carrying a bulging cane grip secured by a brown leather strap.
 
Seeing Harley on the step, she paused for a moment, then, recovering herself:
 
“Ellen!” she shouted down the dim passageway revealed by the opening of the door. “Somebody to see you.”
 
Leaving the door open, she hurried past the visitor with averted face. It was well done, and, thus disguised by the thick veil, another man than Paul Harley might have failed to recognize one of whom he had never had more than an imperfect glimpse. But if Paul Harley’s memory did not avail him greatly, his unerring instinct never failed.
 
He grasped the girl’s arm. “One moment, Miss Jones,” he said, quietly, “it is you I am here to see!”
 
The girl turned angrily, snatching her arm from his grasp. “You’ve made a mistake, haven’t you?” she cried, furiously. “I don’t know you and I don’t want to!”
 
“Be good enough to step inside again. Don’t make a scene. If you behave yourself, you have nothing to fear. But I want to talk to you.”
 
He extended his arm to detain her. But she thrust it aside. “My boy’s waiting round the corner!” she said, viciously. “Just see what he’ll do when I tell him!”
 
“Step inside,” repeated Harley, quietly. “Or accompany me to Kennington Lane Police Station—whichever you think would be the more amusing.”
 
“What d’you mean!” blustered the girl. “You can’t kid me. I haven’t done anything.”
 
“Then do as I tell you. You have got to answer my questions—either here or at the station. Which shall it be?”
 
He had realized the facts of the situation from the moment when the girl had made her sudden appearance, and he knew that his only chance of defeating his cunning opponents was to frighten her. Delicate measures would be wasted upon such a character. But even as the girl, flinging herself sullenly about, returned into the passage, he found himself admiring the resourcefulness of his unknown enemies.
 
A tired-looking woman carrying a child appeared from somewhere and stared apathetically at Harley.
 
Addressing the angry girl: “Another o’ your flames, Polly?” she inquired in a dull voice. “Has he made you change your mind already?”
 
The girl addressed as “Polly” dropped her grip on the floor and, banging open a door, entered a shabby little sitting room, followed by Harley. Dropping onto a ragged couch, she stared obstinately out of the dirty window.
 
“Excuse me, madam, for intruding,” said Harley to the woman with the baby, “but Polly has some information of use to the police. Oh, don’t be alarmed. She has committed no crime. I shall only detain her for a few minutes.”
 
He bowed to the tired-looking woman and closed the sitting-room door. “Now, young woman,” he said, sternly, adopting this official manner of his friend, Inspector Wessex, “I am going to give you one warning, and one only. Although I don’t think you know it, you have got mixed up with a gang of crooks. Play the game with me, and I’ll stand by you. Try any funny business and you’ll go to jail.”
 
The official manner had its effect. Miss Jones looked sharply across at the speaker. “I haven’t done anything,” she said, sullenly.
 
Paul Harley advanced and stood over her. “What about the trick with the serviettes at Sir Charles Abingdon’s?” he asked, speaking the words in slow and deliberate fashion.
 
The shaft went home, but the girl possessed a st............