Whispering Death

THIS book is a product of a collaborative effort undertaken by Project Gutenberg Australia, Roy Glashan's Library and the bibliophile Terry Walker to collect, edit and publish the works of Aidan de Brune, a colourful and prolific Australian writer whose opus is well worth saving from oblivion.

LIST OF ILLUSTRATIONS

Illustration 1. Headpiece from "The World's News."
Illustration 2. Dr. Night and the "Gravity Plane."
Illustration 3. "Now, I'll give you a tip. Watch Bob Hardy."
Illustration 4. The evil Dr. Night.
Illustration 5. "I know him, sergeant. Roy Iston, of the Mirror."
Illustration 6. Inspector Frost listened to his account of the day's happenings in silence
Illustration 7. "He'll want bigger, heavier and faster planes of the gravity type.
Illustration 8. "Cracked up by that scoundrel, Dr. Night..."
Illustration 9. The detective stood up and flashed the light of his torch on the white face.
Illustration 10. For some moments Roy stood surveying the room.
Illustration 11. Seated in his wheeled chair, beside the table on which the globe stood, was Adam Halliday.
Illustration 12. "What's the matter?" Roy opened his drowsy eyes.
Illustration 13. "But—you would not have had Wales pay over the money?" the newspaper-man exclaimed.
Illustration 14. "Complying with the demands of a blackmailer? Of course not."
Illustration 15. Large clouds of light-blue smoke rolled into the room.
Illustration 16. "Well, what are you going to do?" Wilson spoke, impatiently.
Illustration 17. To his utter astonishment he read the name—"Dr. Night."
Illustration 1. For some moments the Master Crook watched Roy in silence.
Illustration 19. "Good story, today. That Britton Chambers got what he deserved."
Illustration 20. "Who's there?" The challenge came in answer to his tap on the window.
Illustration 21. The mist slowly dispersed, and where the mystery man had stood there was nothing.
Illustration 22. He dragged the inspector inside as the sinister whispering grew louder.
Illustration 23. "Guess you recognise you're beaten."
Illustration 24. "Listen! I'm a prisoner."
Illustration 25. "Roy! Is that you, Roy!"
Illustration 26. She glanced downwards.
Illustration 27. "Albert Wilson's Murillo."
Illustration 28. "I most certainly am coming."
Illustration 29. "Australian warrants don't hold in this country, Inspector."
Illustration 30. Doris was pulling the slender chain fastened to his coat.

CHAPTER I

Roy Iston halted at the door of the big reporters' room in the Mirror offices, gazing around him with an expression of comical dismay on his homely, cheerful features. For a bare moment he hesitated, then strode across the long room to the large horseshoe table at which three men sat. He looked down at them with wonder growing in his eyes.

The three men were bending forward over the table, their foreheads resting on a confused litter of papers. Almost fearfully, Roy went round the desk and laid his hand on the shoulder of Robert Hardy, the chief sub-editor, shaking him gently. The man's head rolled grotesquely on the papers and he gave no signs of consciousness. Roy bent lower. Hardy's face was deathly pale; his lips were slightly parted and on his clenched teeth was a film of dead white foam.

Roy straightened himself with a jerk, withdrawing his hand from the man's shoulder as if the contact had stung him. He glanced down the big room, a frown of perplexity on his ruddy face. At many of the desks men were seated, each of them bending forward over his work. From where he stood, Roy could see that they were unconscious.

"The cuckoos!" A soundless whistle formed on his lips. "What the hell? The whole staff of the Mirror doped, or—" He shook his head, as if in negation, of the thought in his mind! No, neither Hardy nor his companions were dead!

Again he bent over the chief sub-editor, forcing him round so that he could peer into the bloodless, pallid features. Hardy was unconscious! But, what had caused it? A couple of paces brought the journalist to Jim O'Sullivan's side. A short examination, and Roy was satisfied. O'Sullivan, like Hardy, was fast asleep.

What had happened during the past three hours—the time since he had left that room on the 'rush' assignment Bob Hardy had thrust on him? Roy's eyes glanced, inquisitively across the room, towards the glass panelled door bearing the words Managing Editor. Behind that door was Alphonse Thomas. Was he, too, unconscious, perhaps dying?

A few strides brought him to the threshold of the room. For a moment he hesitated, then rapped sharply on the glass. There was no answer. He waited a few seconds before turning the handle and entering. The managing editor was seated at his desk, his head resting on his arms folded on his blotting-pad. A quick examination and Roy decided that he, too, was fast asleep. Almost on tiptoe, the journalist stole into the big, room, closing the door behind him.

What had happened? The frown deepened on Roy's face. The affair was almost unbelievable. He threw a quick glance at the many doors opening from the reporters' room. He knew that if he opened any of them he would find the occupants asleep. For the first time a sense of loneliness overtook the journalist. He shuddered, thinking of himself as the one sentient being in that building of sleepers.

Almost involuntarily, he turned to the doorway through which he had entered, then hesitated again. There was something in the atmosphere of the place that puzzled, nay more, perplexed him. Something more than the muted men seated around that room.

For a time he debated what he should do. He listened; there was not a sound. In that building at that time of night the Mirror offices should be vibrating with the shrill clatter and dull thuds of the speeding linotype machines. From deep down in the bowels of the building he should hear the reverberation of the mighty presses getting ready, to print the far-country editions! It wanted but a few minutes to eleven and at twelve-fifteen the first edition should be on the machine!

Mechanically, Roy strode up the long room to the sub-editor's table and drew to him one of the telephones. For some minutes he listened with growing impatience for the answer from the switch-board operator, then suddenly laughed.

"Of course!" Again he laughed. "The girl at the switch is also doped. Well, I'll have to attend to myself."

A few strides took him to the door. In the little room stood a! large switchboard. Before it was seated a girl, the earphone on her head her fingers holding a connecting cord. But she lay back in her arm-chair, sound asleep. Across her knees stretched the office-cat, snoring loudly.

"Oh, Maisie, Maisie!" Roy shook his head, comically. "And all those connections chattering like a lot of old maids at a tea-party!"

Ignoring the 'buzz buzz' that sounded from nearly all the lines coming into the office, Roy found an unoccupied line and plugged in. Then he dialled Police Headquarters.

"Police Headquarters? Good!" Roy spoke after a short pause. "Put me on to Inspector Frost. Yes. Roy Iston, of the Mirror speaking. No; none of that thanks. I was talking to him ten minutes ago and he told me that he had a couple of hours' work on hand before he could go home. Yes, I'll hang on. Bet your sweet life! Speed-o, boy!"

"That you, Jim! Good! Roy Iston speaking. Say, can you come over to the Mirror? Important? I should say it was. Battle, murder, sudden-death—or slow, perhaps! Take your choice! No, I'm not rotting, Jim, it's real important. Best case you'll have in your young life. Coming? Good-o!"

Thoughtfully, Roy replaced the receiver and went back to the reporter's room. For a minute he waited; then turned to the door leading to the elevators. It seemed inhuman to leave his friends, unaided; but he; did not want to touch them, yet. He wanted the room to remain as it was until after the Inspector's arrival. He wanted definite logical answers to the many questions that crowded his brain.

Again at the big, swing doors, he hesitated, then pushed through and went on to the pavement. The hands pointed to eleven-fifteen. He stared, doubtfully, up at the clock. Had only twenty minutes passed since he had pushed through the swing doors behind him, intent only on getting to his desk and scribbling the few lines of copy required—and then leave for home? In those few minutes he had lived hours. He had passed from the streets of the living to the habitations of the dead—

The dead! Had he been mistaken in his diagnosis and were the men in the building dead—not sleeping?

Dead! Dead! The words echoed again and again through his brain. He shook himself angrily. Why should he continually harp on death? He knew that Bob Hardy was not dead—merely sleeping. But, why? How? What—no, who—had caused the sudden sleep of nearly a hundred humans in the heart of one of the most important cities of the Empire?

"What's up Roy?" A heavy hand on the journalist's shoulder startled him from reverie.

"Up?" A slow grin came on Roy's face. "Come up, and I'll show you. Ever been in a city of dead men, Jim?"

"Dead men?" The Inspector, a short, keen-faced, dark man, looked suspiciously at the journalist. He spoke sharply. "This isn't one of your jokes, Roy, is it? If it is, the Lord help you! I'm as busy as an ant's great-grandmother."

"Joke?" Roy shook his head, gravely. "Wish it was, old man. I'd give a weeks' pay to—oh well, you know left you half-an-hour ago." He glanced up at the clock. "In front of headquarters, y'know. You turned in, there to—to do what all good policemen do before they go home I suppose."

"Well, I came on here." Again Roy smiled, involuntarily. "Pushed through these doors. Went up in the automatic lift to the third floor. Went to go to my desk to write up—well, that doesn't matter—and found the whole house asleep."

"You've said it!" The newspaperman nodded his head. "I'd have said the same thing, if you'd told the tale! As it is, come and see!"

"Joke?" The journalist's face suddenly showed the strain of thy past few minutes. "If I'm joking, Frost, put me in an asylum—put me in the condemned cell, or—or kick me back to front. You've my leave, but come on, man! Come on!"

He wrenched himself from under the Inspector's hand and darted into the building. Frost, a look of doubt on his hawk-like face, followed slowly. In silence, they went up to the editorial offices.

Flinging open the door of the reporters' room, Roy stood aside for the police officer to precede him.

"God!" Frost paused on the threshold, taking in the sprawling forms of the men at the various desks. A quick glance around and he sprang to action, half-running to the sub-editor's dock, at the head of the room.

"He's alive!" The inspector bent over Hardy's unconscious form. "Here—I want a doctor. Quick!" He caught up the telephone, agitating the hook angrily. "No good!"

Roy laughed nervously. "Wait!' I'll switch through from the board. Get a doctor's number and stand by."

In a few minutes the newspaperman re-entered the big room. The Inspector was speaking into the instrument. He replaced it on the table and turned to the unconscious man.

"Give me a hand, Roy. I want to lay him on the floor. No," he exclaimed, noticing the journalist's hesitation. "He's not dead—but he's in my way!"

In silence, they lifted Hardy from his chair and laid him on the floor, Roy slipping a seat-cushion under the man's head. Frost slipped into the sub-editor's chair and drew the papers on the desk towards him. Immediately, he gave a short exclamation.

"Here, Roy! Seen this before?" The journalist bent over the sheets of copy paper, reading quickly:

Shortly after ten o'clock last night the lighthouse keeper at South Head reported a strange aeroplane coming to land from due east.

The plane bore no letter or distinguishing, marks and was only about five hundred feet above the lighthouse.

Mr. Seeman, the head-keeper, reports that the plane was travelling at a tremendous speed and headed directly for the centre of the city. He is certain that it does not belong to the military or naval authorities of the Commonwealth, nor it is the property of any of the numerous aero clubs.

The most remarkable thing about the mystery plane is that the engines, which evidently develop enormous power, are absolutely silent.

Whence came this mystery ship and who owns it? It is certainly a distinct improvement on any other aeroplane in the Commonwealth and a most potential weapon of destruction.

The mystery airship hovered over Sydney for some ten minutes, plainly visible to many observers. It then headed seawards, travelling at a....

There the message ended abruptly. The journalist and the policeman stared at each other in blank amazement.

CHAPTER II

ROBERT HARDY opened the door of the managing editor's office, in the Mirror building and glanced round the reporters' room. He caught Roy's eyes and beckoned; then returned into the room, leaving the door ajar. Roy shuffled his papers together and sauntered across the room. He tapped on the glass of the managing editor's door and immediately entered. Bob Hardy was standing beside Alphonse Thomas. Both men nodded shortly to the young man.

"It was certainly intriguing." Roy smiled tightly, and continued. "I may say that was the first time I've caught my chief sub. asleep."

"I've asked Mr. Hardy if he would take the assignment." The managing editor spoke testily. "Unfortunately, he cannot. He's recommended you. Take it?"

"To discover who played the trick on the Mirror?" Roy spoke eagerly. "Why, sir—"

"We know who played the trick," Hardy interrupted. "The gentleman was good enough to leave his card last night. Found it in my pocket, this morning."

"That's why I wanted Mr. Hardy to follow this up." Thomas spoke impatiently. "He came across this scoundrel, once before, and—'

"You mean Dr. Night?" Roy knew the story of the battle of wits between the mysterious Asian, Dr. Night and Robert Hardy in the days when the latter had been a reporter on the Mirror's staff—a story that contained the love romance of Hardy and his wife.

"We trust you, Roy." Hardy spoke gravely. "We are in doubt, however, whether we should allow you to run this risk. Dr. Night is a killer; one of the greatest—perhaps the greatest—criminals in the world. You stake your life?"

"I was lucky." Hardy drew a card from his pocket and passed it to Roy. The journalist examined it, curiously. It bore only the words "I have returned—Dr. Night."

"That we can only guess at." Hardy motioned the journalist to a chair. "Dr. Night, years ago, told me that he was at war with the white races. I believe—I have reason to believe that he is the last survivor of some royal race who held empire in the heart of Asia. That is surmise only. We know so little of him."

"Yes." Hardy passed his hands over his eyes, wearily. Then he spoke suddenly 'God! I'd give ten years of my life to go after that scoundrel, again!'

"He's a married man, youngster." Thomas spoke ironically. "Can't say I blame Mrs. Hardy. She had a bitter experience of this Dr. Night. Anyhow, she's put her foot down. Hardy has to remain in the safety zone. You take his place. Willing?"

"Then listen." Thomas paused a moment. "You came up here last night and found us all asleep. We took some waking, I believe. Now, here's the story: About half-past ten last night, Mr. Seeman, of the South Head lighthouse, telephoned Hardy about a mystery 'plane he had seen coming over the heads; from the sea. Hardy was taking the message when he chanced to look up and fancied he saw—"

"Well—looked up and saw Dr. Night standing in the doorway. The Asian was smiling mockingly. He lifted his hand and disappeared. Hardy found that the atmosphere had become thick; he could hardly breath. He fought for consciousness and—and watched his comrades, one after the other, come under the influence of the gas—"

"Gas?" queried Roy, curiously. "I did not smell anything when I came into the room."

"Here and now." Thomas nodded, appreciatively. "You've got the tale, so far as we can tell you. Hardy will put you wise to anything you want to know regarding Dr. Night's previous visitations. You can work, so far as the police will allow, with Inspector Frost—"

"I've had a word with the Commissioner," Thomas nodded. "Frost knows Dr. Night and his methods. Perhaps he'll be able to keep you out of mischief."

"If you do you'll wear the sack," thundered the managing editor, grimly. "No, Hardy spun along ahead of the police when he went after Dr. Night. We expect you to do the same. Still, boy, don't neglect Frost. He's a clever, keen man, and he knows what he's up against—and you don't."

"Act as you deem wise, Roy." Hardy spoke kindly—"You've got more than I had, when I took up Dr. Night's trail, years ago. We know the man and his methods, and with Inspector's Frost help can guard against this uncanny powers. I know how far he will go before he acknowledges himself beaten."

"Yes." Hardy spoke quickly. Roy looked from one man to the other, in perplexity, then laughed. A moment, and the three of them were laughing, together.

"For the time being I'm going to link up everything I can with the mystery." Roy spoke after consideration. "There's the 'plane, the gassing and this card. That's all." He hesitated. "Unless you can supply the remainder of the missing report."

"The papers on Mr. Hardy's desk concluded with a 'late' message he was taking over the 'phone." The journalist addressed himself to his managing editor. "The words were-" He pulled a sheet of paper out of his pocket and read:

"The mystery 'plane hovered over Sydney for some ten minutes, plainly visible to many observers. It then headed seawards, travelling at a-" Roy paused and looked expectantly at the chief sub.

"That all?" Roy showed his disappointment. "Nothing about where the plane was going to. Not a word to indicate-"

"I can't remember." Hardy showed perplexity. "When I re-read that message last night I could not even remember taking it over the 'phone. Yet, it is in my handwriting. No, I can't imagine what the missing words may be."

"Strange, isn't it." Thomas nodded, vaguely. "A mystery 'plane hovered over Sydney—or is said to have done so. Someone telephones Hardy a story about it in Seeman's name. At the same moment, Dr. Night calls on Hardy and leaves his card—and the lot of 'em asleep."

"It came from the sea; it returned to the sea," said the managing editor, serenely.

"Guessing is unprofitable." Thomas warned. "Now, Roy, get busy. You report only to Mr. Hardy or me. Understand? I want Dr. Night. Frost swears to plant him behind prison bars. You've got to race him to Dr. Night and get his story, first. Now Hardy-" He turned from the journalist. "There's that matter of staff-grading? Oh, damn that 'phone!"

The shrill tring of the bell had cut in on the managing editor's words. He lifted the receiver and as he listened wonder grew on his face. For a moment he sat, motionless, then signed for Roy to take the instrument.

"—and I trust Mr. Hardy took no effects from his little adventure last night." A cold, rather monotonous voice spoke over the wire. "I regret he did not publish the message I gave him over the telephone."

"The message regarding the mystery 'plane?" asked Roy, imitating Thomas's voice.

"Yes." The level tones continued. "I intended that message to prepare the good business men of Sydney—to prepare them for my demands."

"I shall ask my business friends of Sydney to contribute to a fund I am initiating—a fund that I shall use to forward the one purpose of my life." The suave voice continued. "I require half-a-million pounds from them. No, I shall not be unreasonable. The poor man shall have nothing to fear from me. I speak only to the rich. In a few days I shall send you a list of the men I expect to contribute to my fund. I trust I they will be reasonable. If not—"

"Uncomfortable things may happen to them. At present, I do not wish to discuss the matter further. You will await my instructions."

"Name?" The cold voice held a trace of amusement. "Ask Alphonse Thomas or Robert Hardy. They will tell you all you require to know regarding Dr. Night."

CHAPTER III

"TOLD me he had a list of rich men of the city of Sydney he expected to contribute to a fund of half-a-million pounds he was raising," Roy spoke indignantly. "Said that he would send on the list to Thomas in a few days and that if these men didn't come up to the scratch he would have to crack the whip. You never heard such bunkum, in all your life!"

Inspector Frost did not answer. He sat back in his chair, fiddling with a paper-knife. From under his heavy brows he watched the newspaper man, keenly.

"I asked him about the mystery plane. He said he owned it; that it was immensely powerful—that with it he could lay waste this city. Then he went on to say that he had caused the sleep that overcame the Mirror staff, last night; that he intended that as a warning to Bob Hardy not to interfere."

"Ah!" The detective drew a deep breath of satisfaction. "So he's frightened of Hardy, is he? What does Bob say?"

"And, as a rich woman, has a pull with the Mirror management." Frost laughed slightly. "Bob won't like that. I should have thought he would have protested, or that Thomas would? No, perhaps there's something behind it all. Bob is no coward; he doesn't care a damn for all Dr. Night's threats. So, you've taken over the chase. Well, I wish you luck!"

"Mr. Thomas says I'm to work with you, as much as the police regulations will let me." Roy spoke ingenuously.

"You've come to me to know where you kick off?" Frost laughed. "That's more than I can tell you, young fellow. So far, there's not a clue in existence. Why, that message—That—might not have been Dr. Night speaking, after all. Some crook—"

The detective hesitated. For some moments he sat, playing with the various articles on his desk. At length, he spoke, slowly: "Listen to me, Roy Iston. You came to the Mirror offices last night, to find the staff sound asleep. Bob Hardy tells you that just before he fell asleep he took a strange message referring to a silent airship. He looked up and thought he saw Dr. Night, standing in the doorway. A couple of hours ago you believe you were talking to Dr. Night, over the telephone. He told you that he had selected certain important business men of this city to blackmail. If the money was not forthcoming when and where he demanded, there was going to be trouble. Eh?"

"The Whispering Death!" Frost paused. "Did he tell you what he meant by that phrase?"

"That's all you have to go on." Again the detective paused. "Look here, Roy Iston, all the police have to go on, as yet, is that last night the Mirror staff fell asleep over their work. Do you think that is a sufficient fact to set our organisation to work on? Why—"

"You're not going to infer, Frost, that they fell asleep by natural means?" Roy spoke indignantly.

"And I cannot conceive any means for doping a hundred men without large preparation and apparatus," the Inspector retorted.

"You don't believe my story, then?" The reporter flushed angrily. "Let me tell you that while I was talking to Dr. Night in Mr. Thomas's room Bob Hardy went to the switch and listened in. He says he can swear that it was Dr. Night speaking."

Roy was silent. Was the mysterious Asian really in Australia? Bob Hardy believed that he was. He knew that Alphonse Thomas shared that belief. But, Frost was doubting.

"Listen to me," the detective continued. "I'm willing to admit that I had an interview with the Commissioner this morning, after he had had a conversation over the telephone with Mr. Thomas. I am instructed to use my discretion. If Dr. Night is in Australia I am to bring him in. But I haven't a bit of evidence, yet, that the man is in Australia. For all I know, he may be in the heart of Asia."

Roy knew that there was truth in the Inspector's statement. They had no evidence that Dr. Night was in Sydney-only Hardy's belief that just before he fell asleep he recognised the Asian standing at the door; that he had heard his voice over the telephone..

And Alphonse Thomas had assigned him to run down Dr. Night! A bitter smile curved the newspaper-man's lips.

Where was he to start? How was he to proceed? For the first time he realised that from the moment he had accepted the assignment he had relied on Inspector Frost for a lead.

Now the detective was pointing out the difficulties in the plainest language. No—only one difficulty, and that was insurmountable.

If Dr. Night had returned to Sydney, where would he be? Roy's thoughts turned to the mystery 'plane. The report that had been sent in to the Mirror had indicated that the 'plane had come to land from the eastern seas. Where, in the wide expanse of the Pacific Ocean, was he to locate Dr. Night?

With a curt nod he turned to the door. As his hand touched the knob, Frost called to him.

"Guess I'll go back and tell Thomas that I'm a bum journalist. Oh, damn it, Frost. What's the joke?"

"I'll help you where I can, Roy," he said, slowly. "But you can't expect me to stir things up on the present evidence—which is not evidence at all. There's just one hint I will offer. Dr. Night makes mistakes—we all do; his mistakes are those of over-confidence. He thinks he's unbeatable. He isn't. Hardy proved that, but Dr Night thinks Hardy's success was a fluke. Maybe it was, I'm not going to give an opinion. Now, I'll give you a tip. Watch Bob Hardy."

The Inspector shook his head and turned to the papers on his desk. Roy hesitated a moment, then left the room and the building.

Watch Bob Hardy! What did the detective mean? On the pavement Roy stopped and pondered. Watch Bob Hardy! But the chief sub. had declined the task of running down Dr. Night. He had said his wife had objected to him taking the assignment.

Was that sufficient reason for Hardy's action? Roy thought of Alphonse's reputation. The managing editor was an autocrat. Although worshipped by his staff, he ruled-them with a rod of iron. He would not tolerate any question to his orders.

Yet he had offered Hardy the assignment, and had quietly acquiesced when the chief sub. had declined it. Roy believed that this was suspicious. Thomas was not the man to allow his subordinates to pick and choose their work. Had he and Hardy an understanding?

Had Hardy's refusal of the assignment been some plot conceived between him and the managing editor? Then—Roy's face flushed as the thought crossed his mind. Thomas's appointment to him to trace down Dr. Night was but part of a scheme to shield Robert Hardy.

The young man's lips set in a straight line. So they intended to use him as a blind. He was to take up the trail of Dr. Night openly, while Hardy worked in secret. In his heart he vowed that he would win through to success, despite his handicap.

He would trace down Dr. Night and bring him to justice. But how? His short talk with Inspector Frost had shown him the difficulties that lay before him. He had nothing to start on. There was not one single clue to guide him on his quest.

Was Frost a party to the scheme evolved between Thomas and Hardy? Roy half-turned to re-enter the Police Headquarters, then swung round and went down to the Mirror offices. What did it matter? Yet he felt very lonely. And but a short half-hour before he had prided himself on the assignment, believing he had behind him the power, influence, and wealth of the Mirror.

In King Street he boarded a tram and went out to South Head. At the lighthouse he found Tom Seeman on duty.

"What of that mystery 'plane, Mr. Seeman?" Roy asked somewhat brusquely. "We didn't get you quite right at the office."

"But you said you didn't telephone through a report of a mystery 'plane coming to Sydney from out sea."

"Neither did I." The man's smile broadened. "But that ain't to say there wasn't one. There was, as it happens."

"But—" Roy stammered. "Oh, damn! Say, Mr. Seeman, was there a 'plane or wasn't there one?"

"There was," Seeman spoke emphatically. "A big 'plane, too. Came in from a point south of east at a tremendous pace. Flying low, too; yet there wasn't a sound from it—just a queer, low, whistling as it passed overhead. I said to my mate. 'That 'plane—'"

"I didn't, 'cos why? 'Cos I couldn't get anyone at the Mirror to answer my call. Now, young man, can you tell me if you were all asleep down there?"

CHAPTER IV

WHEN Roy Iston left the managing director's office Alphonse Thomas did not resume work. He sat back in his chair and waited for Robert Hardy to return to the room.

"The telephone message came from a public call-box at the William Street Post Office." Hardy spoke shortly. "Where's Roy Iston?"

"Gone to interview Inspector Frost." A slight smile parted Thomas's lips. "What will Frost tell him?"

"Nothing." Hardy paused. "Nothing more than he has told us this morning—that the Department cannot move on the story as it stands now."

"That would be unlike Frost," Hardy smiled. "Before Roy has spoken half a dozen sentences Frost will guess the game we are up to. Frost won't willingly believe that I would relinquish any chance to get even with Dr. Night."

Thomas nodded. "Think we're dealing fairly with that young man?" he asked shortly.

"Roy?" Hardy frowned. "I don't like it one bit, Mr. Thomas, but what else can we do? Dr. Night must not suspect I am moving against him. It will be impossible to make him believe that the Mirror will not accept his direct challenge—for that is what his actions last night amount to. He will believe that you will give me the assignment to hunt him down, and he will be on his guard. He will have me watched. If I am to do any good I must have freedom of action. Someone from the Mirror has to go after him. With your consent I chose Roy Iston."

Hardy smiled. "Good luck to him. He can't do any harm—and he will deflect suspicion from me. If he beats me to the story you know I'll be the first to congratulate him."

Thomas nodded. For some minutes he sat meditating. "What do you intend to do, Hardy?" he asked at length.

"Wait." The sub-editor made a gesture of impatience. "There is not a single clue for us to work on at present. Yet Dr. Night has shown that he fears us. His gassing of the office last night shows that In a day or so he will move again. Perhaps then he will make some mistake that will give us a starting point.",

The managing editor spoke slowly. "Our first bout with him occurred when he was engaged gathering a war-chest by means of the drug traffic. Then came the incident of the Green Pearl. I understood that he claimed that jewel as belonging to his ancestors What is he after now?"

"I don't know." Hardy spoke perplexedly. "But I do know that this time we are after him, and, by little apples, we'll get him."

With that the journalist rose abruptly from his chair and left the room. He had barely seated himself at his desk before the telephone bell rang.

"All right. Send her in." Hardy sat back in his chair and watched the door. In a few seconds a young, fair-haired girl entered, following a copy-boy, and looking around her inquiringly The boy led to the chief sub's desk.

When Bob nodded she continued. "I am Ruth Halliday. My father asked me to call and give you this." She held out a letter as she spoke.

Hardy tore off the envelope and drew out a single sheet of paper There were only a couple of lines of writing, and he read them at a glance. He turned to the girl.

"Yes." The girl hesitated. "It is a request from my father for you to call on him." She paused, then turned to fully face the journalist. "Mr. Hardy, will you do as my father asks? He is a cripple—crippled in the war, but he is really clever. He has something—something he wants to talk to you about—something to show you."

"No." The girl's face lost its animation. "He will not tell us—mother and me. All he will say is that he has chanced on a great secret and that there is danger attached to it."

"That is all you know?" At the girl's nod of assent, Hardy continued: "Do you know why your father wants me to call on him? So far as I know, we have never met."

"Father told me that if you asked that question I was to reply that you had knowledge of a certain Chinaman."

"No. I only know that through that Chinaman you and your wife nearly lost your lives." The girl answered simply.

"We have enough to live upon." Ruth Halliday spoke after a slight pause. "Father has a workshop and tries to invent things."

"Has he invented anything?" Immediately Hardy changed the question. "Do you know the name of the Chinaman you mentioned?"

"Not his Chinese name." The girl smiled. "He has an English name but I have forgotten it. I saw him once, when he called on father. He is a slight, grey man; dresses in grey and speaks in a slow, very polite voice, with just a suspicion of a foreign accent."

For a moment Hardy hesitated, then reached for his hat. The girl rose from her chair with a little smile of thanks and led from the room. In the street she pointed to a small, dark-blue sports car.

"I thought you would come, so I brought my car for you. It will be quicker and nicer than going out to Vaucluse on the trams."

During the drive Hardy watched the girl closely. From the moment he recognised Dr. Night standing at the door of the reporters' room the previous evening he had been keenly on guard. He guessed that he was in danger and that only the most constant watchfulness would serve.

He knew that Dr. Night feared him—feared the luck that had brought him successfully through the battle of wits he had fought with the Asian. In those days, half-a-dozen years before, Dr. Night had treated him with contemptuous tolerance. He had watched and waited, content to abide his time. In the end he had smashed up the huge drug ring the Asian had created and had forced the master-criminal to flight.

He wondered if this girl was an agent of the Asian. If she was not then here again was the long arm of coincidence, for if she was acting in good faith then her visit to the Mirror followed very closely on Dr. Night's challenge.

Hardy did not fear for himself. He had faith that he could get out of any predicament he happened into. But he was determined he would not be caught off his guard if he could possibly prevent it.

The girl drove the little car out to the suburbs at a smart pace. A few hundred yards from the town of Vaucluse she turned from the main road, towards the harbour. At the foot of a steep hill she drew the car to a stop before a comfortable-looking house.

"Father is down at the shed," she said. Then, noticing Hardy's questioning glance, she smiled. "He is always on the front veranda or at the shed." she explained. "You see, he is not on the veranda, so—"

She led down a path beside the house to a fair-sized garden at the rear. Hardy looked about him, curiously. They were walking towards a rather large brick shed. As they drew near, he noticed, that the place was strongly built and furnished with a heavy iron door.

"No." Suddenly, she became grave. "But the second burglar got in. I think he managed to tamper with the lock. The alarm sounded and father fired a shotgun at the door. There were specks of blood on the lintels the next morning." She broke off, suddenly. "Father!"

The door swung open and a man propelled a small, wheeled-chair, in which he was seated, into the garden.

"Father, this is Mr. Hardy. He was so good as to leave his work and come with me at once."

Hardy looked at the man before him, curiously. He had a keen, thin, clever face, surmounted by snow-white hair. The journalist noted that both Halliday's legs had been amputated below the knees.

"Good of you to come so quickly, Mr. Hardy." The man's voice was strong, yet pleasant. "I am sorry to say I have had a severe loss."

"The police cannot help me." A twinge of pain crossed Halliday's expressive features. "But I believe you can."

CHAPTER V

"SO Dr. Night robbed you of—something?" Bob Hardy spoke after a short pause. "And you come to me to recover it?"

"Hardly that." Bob smiled. "I had luck and the police on my side. Against me—But, tell me what Dr. Night has stolen from you?"

"The Whispering Death." Halliday spoke in a low voice. "No." He moved his hands impatiently. "He did not steal it; he took it."

The Inventor swung his chair round and led into the building. As Ruth went to follow him he ordered her, brusquely, to go up to the house.

"Come in, Mr. Hardy." Halliday waved his hand in a sweeping gesture. "Welcome to my cave of dreams; my last interest in life."

"What is the Whispering Death?" Hardy glanced around a room that was partly laboratory and partly workshop.

"The most terrible engine of destruction ever evolved from man's brain." Halliday sent his chair, with a powerful push, along a low bench to a far corner. "Look, Mr. Hardy, here are photographs of my model. Unless you interfere, successfully, within a few days one of these machines will be hovering over Sydney, raining down death and destruction, with impunity."

Hardy bent over the photographs on the table. They showed what appeared to be an ordinary plane, yet there was something strange about it. He looked at the inventor.

"An aeroplane." He lifted his eyebrows slightly. "What is there about it, Mr. Halliday, to distinguish it from the dozens of ordinary 'planes that cross Sydney daily?"

"Look again." Halliday pushed his chair nearer the table. He lifted a pencil and tapped a section of the photograph. Hardy looked closer.

"A complete model. No. Look well, Mr. Hardy. Every detail of construction is there. What do you think is missing?"

"The propeller—yes—why, man, the machine has no engines. It's a glider, perhaps a sailplane—and you call it the 'Whispering Death!' Are you—"

"Can a sail-plane, or glider, travel at five hundred miles an hour?" There was gloomy triumph in the inventor's tones. "The Whispering Death will do that—possibly more. No, Mr. Hardy; the Whispering Death has no internal combustion engines. It is driven by a new force, the dream of scientists, but never before realised."

The wheeled chair swung round and roiled to a bench in another part of the large room. Occupying the centre: of the bench was a large globe, set on-a spindle. Hardy immediately recognised a model of the earth.

Beside the sphere rested a delicate little model of an aeroplane, beautifully finished to scale and exact in detail. But the model, barely two inches long, bore no propeller. Halliday touched a switch and the globe started to revolve slowly. He touched another switch and from across the work-bench a powerful beam of light lit on the revolving sphere.

Again the inventor touched a switch. Hardy wondered, for nothing appeared to happen. The man in the wheeled chair lifted the little aeroplane and held it over the globe, about two inches above the surface. For a minute he held the 'plane, then released it. Instead of falling the model remained suspended above the globe.

"There is the Whispering Death. There is no weapon to equal it known to men. It has no engines, uses no petrol or oil. It has speed beyond the dreams of aeroracers. It is the super-aeroplane—mine."

The inventor's fingers went to a row of knobs on a board screwed to the edge of the bench. As he touched them, one after the other, the little 'plane circled, dipped and rose Hardy gasped in astonishment.

For minutes he stood, watching the little toy while the inventor played with the controls. He bent closer to the little machine, and then became aware of a slight, subtle sound, coming from it. For a long time he remained motionless, listening.

"The Whispering Death!" He straightened and looked at the inventor. "So that is why you named it the Whispering Death?"

The man nodded. "Where the sound comes from I cannot explain. There are no moving parts in the machine. Only in one way—" He broke off, suddenly.

"Dr. Night stole a complete set of plans for a full-sized machine. He stole a full-sized machine, nearly completed." Halliday spoke bitterly.

"No burglar could enter here. This workshop is protected so well that it would be death to anyone who penetrated beyond that door without my permission. No, Dr. Night came through the door, a visitor."

"How he came to know of me I do not know." Halliday spoke without inflection. "He came here, he told me, having heard rumours that I had invented a new 'plane."

"Perhaps it was my vanity that betrayed me," the inventor continued. "I had spoken to no one of my experiments. I should have known that he must have spied to have learned my secrets. Instead, I invited him here and showed him that toy."

"I explained to him the principle of my discovery. Somehow he drew me to talk. I told him of the dreams of power I had for my country when I had finished my experiments and had perfected my machine.

"Then, one day, he came here while I was working. I had come to look upon him as a friend. He said he wanted to help me, and laid on that bench banknotes for ten thousand pounds. That was not to be the price of the machine, it was money in advance to help me conclude my experiments quickly. I was to hire what help I required. As soon as possible I was to commence the erection of a full-sized machine. When that was built he would undertake the sale of it to the Australian Government."

Halliday motioned to his wheeled chair—to all that remained of his lower limbs.

"How am I to negotiate,'" he asked bitterly. "I am unknown, working in secret. How am I to travel about from Government office to office, interviewing many people; conducting negotiations on all sides. No, from the first I realised that I could not do that; that some day I should have to take someone into my confidence. I thought that I had found a trustworthy agent in Dr. Night—a rich man who would work for the good of his country."

"But you knew that he was not an Australian!" Hardy exclaimed in astonishment. "Dr. Night is an Asian—why, your daughter spoke to me of him as a Chinaman."

"I know now. I knew but a few days ago, when he came to see me and boasted of his power and his race. I did not know when he first came to me."

"Four months ago; that is two visits before he brought me the money Then I went to work and completed my experiments. He asked me for the plans to build a full-sized machine. Later he came here in a handsome car and drove me out to the factory where the machine was to be built. It was then I had my first doubts of him. The factory was manned, almost exclusively, by Asians. Only the manager and a couple of men—subordinates—were white."

"Everything except the key-plans to the secret power that lifts and flies the machine." The inventor answered. "That apparatus is small. Dr. Night suggested that I should manufacture that myself, to preserve my secret. I did."

"But, if you preserved the secret plan, what use were the other plans to Dr. Night?'

"I completed the secret apparatus about the time the rest of the machine was ready." Halliday paused. "Dr. Night suggested that he and I make a secret test of the machine the night before last! I was thrilled at the thought of ascending above the earth in the creation of my brain, and consented. He came for me that night in his car, accompanied by a couple of Chinese servants to carry me and the apparatus. They carried out the apparatus while Dr. Night waited with me, here."

"Suddenly Dr. Night commanded me to look at him. I did, and found myself held in thrall. I could not move, speak, or cry out. He left me like that, to await discovery by my wife and daughter, long after midnight. He drove away with the key-apparatus to my aeroplane."

"Then the mystery 'plane that flew over Sydney last night was the Whispering Death!" exclaimed Hardy.

In a few words Hardy explained the happenings at the Mirror offices the previous night.

"That was my machine." Halliday raised himself in his chair with a sudden effort. "If I could get my hands on him!"

"What did he promise you for the 'plane?" asked Hardy, after a long pause. He could not think of Dr. Night descending to deliberate theft.

"Jumping tin hares!" Hardy could not restrain his laughter. "Why, that's the identical sum he proposes to blackmail the rich men of this city for."

CHAPTER VI

FOR some time the inventor and Hardy sat in the laboratory at the foot of the Vaucluse garden, discussing Dr. Night and his theft of the Halliday 'plane.

The invalid inventor had taken a sudden liking to his companion. Before sending for Hardy he had learned much of him; many things, peculiarly, from the mysterious Asian, Dr. Night. Halliday now knew that Hardy was trustworthy.

That mattered much to him. For more than a dozen years he had lived in his little wheeled chair, at first morose and solitary; then withdrawing still more into himself as the idea of the gravity 'plane came and developed in his mind.

Their success had caused him to withdraw from the world around him. He had almost completely cut himself away from his wife and daughter; living all his days in the laboratory; even taking his meals there. Many nights he refused to leave the place, tossing restlessly on the pallet bed he had had installed in one corner.

And as his hopes dawned for the success of his experiments there came dreams of great wealth. He knew that, his aeroplane once in the air and performing as he desired, he had the world at his mercy. No engine of destruction or commerce could live with his creation. Cities, nations, would have to bow to his imperial will.

Yet, in spite of the dawning knowledge of the power he was creating and the use he could make of it, Adam Halliday was true to his creed and nation. For himself and those kin to him he desired ease and comfort. For his Empire he planned supremacy—a superiority in the councils of the nations that could, not be challenged.

Through his dreams obtruded one thought. He was a crippled invalid; an inventor unknown and unhonoured. To gain acknowledgment of his success, when it came, he would have to mix with men on an absolute equality. He would have to come and go freely. How could he do that when he was chained to a wheeled chair?

Then Dr. Night had come to him. The cold, suave manner of the Oriental had completely deceived him. The pose of, great wealth, to be used to further a world of peace and justice, had evoked his confidence. He had given the man his secrets—except one. The secret of the unknown metal constituting the gravity box—the basic secret of his invention.

Now to him had come Robert Hardy. He had not to judge the journalist on his appearance, his words. Chance had brought to him a full knowledge of the man and his history. He knew that in Hardy he had the one instrument to set against the machinations of the Asian. He believed—nay, he was certain—that the journalist would again triumph over Dr. Night and retrieve the big mistake he had made.

Hardy stayed at Vaucluse until the afternoon was well advanced. Then Ruth Halliday offered to drive him into the city. Hardy accepted with some eagerness. He did not relish the long, slow journey in the tramcars.

The journalist left Halliday with a promise of a quick return. In the city Hardy intended to go straight to police headquarters and consult Inspector Frost. A guard and a watch must be set about the Halliday home and the laboratory. Dr. Night or his agents would return. The Asian had the 'plane fitted with the secret gravity-power; but he had no knowledge of the metals the plates were composed of He had the Whispering Death, but to duplicate it he would have to obtain from the inventor his secret formula—the formula of the repulsion plates that gave the machine its wonderful locomotion. Halliday was certain that no experiments nor analysis would yield the secret of the unknown metals.

Probably Dr. Night had by this time realised that he had been hasty in so abruptly alienating the inventor's trust in him. No doubt he had himself, or by one of the numerous agents he employed, tried to duplicate the plates. He had certainly failed. Now he would again turn his attention to Halliday. This time he would not have a solitary, trusting man to deal with. The inventor would be on his guard—he would be guarded. Dr. Night would have openly to avow his quest. He would first, thought Hardy, attempt a search of the laboratory, in the hopes of obtaining some memoranda of the formula. Failing in that direction, he would endeavour to take captive Halliday, and wring his secret from him.

"I am glad I brought you out to see father," Ruth spoke impulsively, after they had driven some distance along the Sydney road in silence.

"He likes you." The girl nodded her blonde head. "Mr. Hardy, father lives too much alone. He has almost deserted mother and me. He is lonely, solitary, spending all his days in his laboratory."

"Come and see him often. Oh, you will be always welcome. Father will welcome you and so will mother and I—not only because you draw father out of himself, but for your own sake."

"Thank you." Hardy meditated a moment. "You know something of your father's worries. I have asked him to confide fully in his wife and yourself. He must never be alone—not even when he is in his laboratory."

"He came up to the house before we drove away." Ruth looked puzzled. "He has not done that for a long time. Usually he goes down to the laboratory soon after daybreak, and only returns to the house at bedtime."

"He will not do so in future." The journalist promised. "Miss Halliday, you and your mother must guard and watch him."

"Much. But I don't rely on you two alone. I am asking Inspector Frost this afternoon to set a guard around your house. From now on, until Dr. Night is apprehended, you will never be unwatched."

"How terrible." Ruth shuddered slightly. "Will we have to live under espionage long?"

"Not very long, I hope." Hardy spoke earnestly. "And to lighten your stress I am going to bring Mrs. Hardy out to visit you and your mother. You will like her—and she will be a safeguard to you all."

"But—your wife and Dr. Night?" Ruth hesitated. "Mr. Hardy, you must not expose her to our dangers."

"Doris will understand." The man spoke confidently. "And she knows Dr. Night. Look out!"

They had turned a corner sharply, almost running into a small crowd gathered on the near side of the roadway. Only the girl's quick resource saved the car from dashing into the people. She swerved and almost immediately came to a halt.

"Someone's hurt." The girl, standing up in the car, could see above the heads of the crowd. Hardy did not wait for any further report. He jumped from the car and pushed towards the centre of the crowd.

A man was lying in the roadway, a doctor and a policeman bending over him. Something in the man's form attracted Hardy. He pushed forward impulsively.

"Keep back there." The constable looked up angrily. "Where do you think you're going?"

"What's happened, sergeant?" Hardy opened his hand to show a little blue covered book, bearing the word "Press."

"Young fellow fell from tram." The constable nodded recognition of the police pass. "The tram was coming down the hill at a pretty bat, too. Pell on his shoulder. Doctor says a broken collarbone and fractured forearm. A couple of ribs damaged, also."

"Whew!" At last Hardy caught sight of the sufferer's face. "I know him, sergeant. Roy Iston, of the Mirror. Should have his police-pass on him."

"Mr. Hardy." The journalist turned, to see Ruth at his elbow. "Is he a friend of yours? You know I have the car here, and—it's a long way to the hospital."

"It's Roy Iston," Hardy explained rapidly. "He's on this Dr. Night story—though what he is doing out this way I can't imagine."

"I am chief sub-editor of the newspaper on the staff of which he is a reporter."

"That makes It better," the girl laughed gleefully. "Tell the policeman to put him in my car with the doctor. We will be home in ten minutes."

"Oh, can't you see?" Ruth protested. "He will be able to tell us what to do—to advise us when you are not at Vaucluse. It is for the best. Mr. Hardy, can't you see what a great thing this will be for us all?"

Almost against his inclinations Hardy instructed the constable to help carry Roy to Ruth's car. The reporter was still insensible when they lifted him. As they propped him in a corner of the seat he opened his eyes drowsily.

"You, Mr. Hardy! Good-o! Where's that tramcar? Hurry, hurry, man Dr. Night was on it!"

"Fell be damned!" Roy closed his eyes again wearily. "I never fell. He pushed me!"

CHAPTER VII

HARDY waited until the doctor had left his patient, then seated himself by Roy's bedside.

"Dr. Night threw me from the tramcar." Roy spoke from amid a wealth of bandages.

"I'll swear he was the man. Besides there was no one else I can think of who would do it."

"Out to South Head, to see Seeman. He told me he did not telephone the paragraph about the mystery 'plane, because he could not raise anyone at the Mirror.

"Had a wander round and a cup of tea—wondering what my next step should be. I caught the tramcar at the terminus and at Vaucluse a man mounted beside me. We were the only two in the compartment. There was a woman further down towards the rear, but she had her back to us."

"Not a word. I almost forgot he was there until going down the hill to Rose Bay. Then he suddenly jerked me to my feet and flung me out."

"Not particularly, except that he appeared all grey—you know what I mean. Grey hair, grey clothes, had that queer greyness of skin that characterises some men. Just what you described in Dr. Night. Oh, it was he, all right."

"And he mounted the tram at Vaucluse?" Hardy pondered. Had Dr. Night spied on him, penetrating the bluff he had put up of hiding behind Roy? That was possible. Or, he might have been watching the Hallidays. In the latter case, had he seen him at their home? If the Asian had, then he would have to abandon all pretence and come out openly on his trail.

"Then it's me for the social activities again," Roy sighed. "Asking budding millionaires how they made their first ten-pound note. Kidding Mrs. Blank that she's the big noise of the new political party."

"Not unless you want to." Hardy laughed "Look here, young fellow. Dr. Night's big enough to keep both you and I on our toes. You've had a slice of luck, though you don't know it."

"Getting into this house as a guest, which I believe will prove the storm centre of the problem." Hardy spoke quickly.

"What do you mean?" Roy attempted to raise himself and fell back with a low cry of pain.

"Keep still, you young fool!" The elder man's voice was kind. "How do you expect to take a hand in the game when you won't give your broken bones a chance to knit? Now, listen."

For a quarter of an hour he spoke quickly, yet emphatically; recounting the story from the moment someone telephoned him the news of the strange 'plane.

"That couldn't have been Dr. Night," expostulated Roy. "You saw him at the door a few seconds' after."

"Couldn't Dr. Night have mesmerised her, got her to call me; then telephone the paragraph from her switch, walk up the passage, and gas the lot of us?"

"He might." Roy paused. "Yes, I believe you're right. He could do that, and more. Now, what can I to do? It'll be rotten lying here, unable to move."

"Then here's your orders. Get well as quickly as possible—and to do that you must stop worrying. Get in the good graces of the Hallidays, especially the old man. He wants cheering up. Keep them from thinking about Dr. Night—and watch."

"Anything that may happen." Hardy laughed. "Oh, something will, sure enough. Dr. Night's got Halliday's 'plane, complete. But he can't duplicate it, for the inventor hasn't passed over the secret of the gravity box that drives the machine. I'm guessing that Dr. Night wants that badly. He'll be after that—and you are here."

"Lacking muscles, use your brain-box. A couple of days and you'll be an interesting invalid. In an emergency you'd be able to move about. Inspector Frost will look to the exterior of the house and the neighbourhood. You're in the centre of the web. When I come up again I'll wise you how you can get in touch with his men, if necessary. Other matters I'll attend to and keep you advised."

"So you found that out?" Hardy laughed. "You're not so dumb, then. No, if Dr. Night was on the tram and threw you out, then he chased after me out here. That stops pretence. S'long, young fellow. Get well and amuse your nurse. She's worth studying."

From Vaucluse Hardy, went to the Mirror offices and, after a short interview with his managing editor, crossed the road to Police Headquarters.

Inspector Frost listened to his account of the day's happenings in silence, at times nodding understandingly. He agreed that the inventor's loss was a starting point in the investigation, and undertook that the house should be watched night and day. It was certain that Dr. Night would make an effort to gain knowledge of the gravity box. Although he had obtained possession of the Whispering Death he must have a complete set of plans if he wished to duplicate it.

"Why not ask why he informed the Mirror that he intended to hold up certain business men for half-a-million," retorted Hardy.

"That's easy." The Inspector laughed. "You say he promised Halliday half-a million for his 'plane. That's what he wants the money for. Dr. Night's queer. He'll steal, but he pays trust with trust. Halliday trusted him with his plans. Dr. Night will wring that half-million from Sydney's business men for Halliday—perhaps a bit more to repay himself for his trouble. Then—"

For a time the two men were silent. At length, Hardy jumped to his feet, in some excitement.

"Remember when I went after him before?" Frost answered with a. nod. "Remember my strange dream, after the explosion under the rocks at Pott's Point? I dreamed that I saw Dr. Night seated on a throne in the centre of some deserted city in Central Asia? That's what he's after and that's what he wants the 'plane for. He's going to conquer the kingdom of his ancestors!"

"Remember what Halliday told me about his 'plane? It doesn't want fuel; it can remain in the air indefinitely. It can travel at what we would call, at present, impossible speed."

Hardy did not answer for some minutes. He leaned back in his chair, a dreamy look in his cool, clear eyes.

"While I was recovering from my previous experience with Dr. Night, in hospital, he said, at length, 'Professor Evans, the Orientalist, came to see me He was curious at what had been published regarding Dr. Night. I told him of my dream—if it was a dream—and he questioned me closely. Finally, he decided that if I had not dreamed the whole thing I had been the recipient of some form of thought-transference from Dr. Night. He made a lot of explanations I couldn't follow and finally decided that the city of desolation I had seen was the capital of Dr. Night's forefathers; that it was situated somewhere near Semarechensk—or, in plain English, The Land of the Seven Rivers.'"

"A successful guess." Hardy laughed. "I looked up the place on a map one day. It is in Russian Turkestan, just outside the borders of the Chinese Empire and not far from the point where China, India, Afghanistan, and Russia meet."

"Opportunities for travel in that direction may be provided for you, later." Hardy spoke significantly. "From all accounts, it is a sweet corner of the world. By the way, Frost, someone libelled that you'd taken up miniature golf."

"You'll have to change your game it you go to Semarechensk, y'know. I understand the people of the Seven Rivers indulge in early rising. The principle amusement is, I believe, going out and cutting a few throats before breakfast."

"I'm certain of it." Hardy was emphatic. "Look here, Frost. Dr. Night has the experimental 'plane, but it's of little use to him if he's going to tackle the Russian and Chinese Empires—and they'll both object to him setting up a turbulent little kingdom on the borders of their territory. Dr. Night doesn't take objections to his plans kindly."

"He'll want bigger, heavier and faster planes of the gravity type. To get them he must gain Halliday's secret formula. He'll do that."

"He'll get it, never fear." Hardy nodded. "I've put in a word to make precautions. Saw Alphonse Thomas before I came here. Fired him up on the mystery 'plane and its possibilities, and he's gone, hotfooted, after Sir Max Vandelere."

"Sir Max is the big noise at the Mirror. He was Minister for Aviation in the last Federal Ministry. He's a bug for aeroplanes—and A. Thomas can handle him. I expect before evening to hear from Sir Max."

"That everyone on the staff of the Mirror is a fool—and that I am the greatest of all. That Halliday is a rogue or the greatest genius the world has ever produced. I shall be called to produce him, pronto. I shall be expected to listen for hours to very technical talk on aviation, between two enthusiasts."

"To keep dud police inspectors in cushy jobs." Hardy spoke dispassionately. "In minor matters, I shall be taken from my work and instructed to supervise the construction of an airliner or two of vast proportions, built to Halliday's specifications, and for which Sir Max will provide the funds. Later, perhaps, I may take flight through China in it, accompanied by Sir Max, other gentlemen, and a famous detective inspector of police—"

"I'm damned if you will!" Frost exploded. "Say, Hardy, where does Halliday keep his secret formula?"

"The damned fool!" Frost rose from his chair and paced the floor. "Don't you realise, man, that if it was a written formula, Dr. Night might steal it, and welcome. Now he'll steal Adam Halliday—and—God help the lot of us!"

CHAPTER VIII

FOR some days Roy suffered too much pain to take much notice of his surroundings; then his healthy youth triumphed and he became restless.

Mrs. Halliday, a thin, somewhat colourless woman, slightly over forty years of age, constituted herself head-nurse and spent many hours each day by the newspaper-man's bedside. Ruth was in and out of the room, continually, yet had hardly a word for the invalid. But Roy noticed that her eyes hardly left him when he was not appearing to take notice of her.

The inventor had seemed to resent the invalid thrust into his house. At first he came at long intervals, as if from a sense of duty. The intervals shortened, under Roy's determination to win the man, until almost without noticing it Halliday slipped into the habit of spending long hours at the reporter's bedside.

Roy had determined that Halliday should be the first to mention his invention. When the inventor spoke of Dr Night the newspaper-man replied briefly and to the point, then dropped the subject. In the end, Halliday broke the ice casually and soon most of their talks centred about the wonderful mystery 'plane and its mission to bring world peace under the aegis of the British Empire.

The journalist, like most youths of the present age, had been greatly intrigued by aviation. That interest had suffered under the fascinations of' newspaper work. Now, with Halliday's encouragement, it revived and soon Ruth declared that the sickroom was unbearable with its continued air of technical acrostics.

Hardy journeyed out to Vaucluse every second day; at first to prime Roy as to the police precautions surrounding the Halliday's home; later he had little to report. A week passed quietly; then one morning the Mirror's chief sub-editor telephoned to make an appointment with Halliday to meet himself and Sir Max Vanderlere.

By this time Roy was permitted to leave his bed and rest on the wide veranda or in the living-rooms of the house. Immediately on the receipt of Hardy's message Halliday invited Roy to be present at the conference in the laboratory at the foot of the garden.

Roy had been, by this time, in the laboratory on several occasions. The little monoplane continually circling the spinning globe fascinated him. He spent hours controlling the miniature gravity-'plane and became so expert in its control that Halliday appointed him exhibitor of the toy at the conference with Sir Max.

"One of my young men," Sir Max, a big, stout man, standing well over six feet in height and ruddy of face, boomed when Roy was introduced to him "Cracked up by that scoundrel, Dr. Night. Well, well! Wonder he never cracked Hardy, six years ago. He's a fool, y'know. Can't tell how he escaped. You a fool?"

"Hope not, sir." Roy laughed slightly "In the office we look on Mr. Hardy as anything but a fool."

"Stick together, eh?" Sir Max's Dig laugh shook the room. "You are mistaken. He's proved himself a fool. What did he want to keep a man of Halliday's abilities covered up for? Stifling a genius, y'know. And, Heaven knows, we want them in the British Empire; with all the younger generation jazzing and cocktailing their brains away."

Hardy winked at Roy behind the big man's back. Then Halliday drove his wheeled-chair into the room. Immediately the baronet's manner changed. He became almost gentle to the cripple—and deferential to the inventor.

"Haven't much time to spare this afternoon, Mr. Halliday," he boomed cheerfully. "Don't blame me; blame the jack-a-napes who run the Mirror. Thank my jinks I've got Alphonse Thomas to look after it; though I can't understand how he can exist surrounded by a pack of idiots calling themselves journalists. Why, if it hadn't been for Thomas I'd never have heard of you, Mr. Halliday. Now, Where's that 'plane—or model of one? Convince me of what Thomas claims for you and I won't run away next visit in a hurry. Mrs. Halliday will have to fetch a broom to get rid of me when she wants to lock up for the night."

Talking loudly, but kindly. Sir Max allowed himself to be led down the garden to the laboratory—the inventor leading in his wheeled chair.

At Halliday's request Roy operated the sphere and the miniature 'plane. Sir Max was interested and examined the toy under a powerful glass, first with the model in his hand and then while it was hovering around the globe.

"Only the rod supporting the sphere." Halliday smiled as he caught the drift of the questions He spun his chair round to another bench and picked up a long, narrow metal box. A flexible wire led from it to a wall-plug.

The lid opened easily. Hardy and Roy drew nearer and peered into the interior. While the outside of the box was painted aluminium white, the interior glistened like molten gold Across the bottom of the box extended innumerable coils of wire. Roy noticed that the whole of the interior of the box was composed of small squares of metal; to each attached the end of a wire. Where the wires led to, he could not tell.

"You notice the switch at the end? Yes? Now, please hold the box very tightly and press the switch."

The baronet obeyed instructions. When he touched the switch a very low murmur filled the room. It became stronger, yet never more than a whisper—an ominous sullen whisper.

Suddenly the baronet's hands, holding the box, lifted from waist high to his shoulders. He struggled to bring it down again, but it continued to rise until, to keep his hold on it. Sir Max was forced to stand on tip-toe.

"Hold tight, Sir Max." A mocking glint shone in the inventor's eyes. "Put your whole weight on it and bring it down again."

The baronet shifted both hands to across the top of the box and flung his eighteen stone against it. But it still continued to rise until it had dragged the baronet off his feet.

With a slight laugh Halliday motioned to Hardy to catch at the box. Now Roy noticed that Halliday held in his hand a small peculiarly constructed switch. As Hardy touched the box the inventor moved the switch—and the box subsided into the men's hands.

"Have I convinced you, Sir Max?" The inventor's cool voice broke the unnerving silence. "No? Well, I will do more—and remember the power in this box is not a tithe of that used in the small aeroplane Dr. Night stole. Please bring me the box, Mr. Hardy."

Halliday pointed out certain straps on his wheeled chair, explaining their purpose "to Hardy. He moved the switch a fraction and the box lost weight. When the straps were attached he gradually moved the arm of the switch over. The box floated upwards. It hesitated a moment when it caught the weight of the chair and scientist. Then it lifted again, taking with it chair and the Inventor. For a full minute Halliday and the box hung suspended above the floor.

"Now your answer, Sir Max?" Exultation rang in the inventor's tones. "I have lifted you from the floor by that box, in spite of your efforts. I have shown you myself suspended between earth and heaven by the power in that box. Have I proved my case?"

"God of Abraham, yes!" Beads of perspiration stood on Sir Max's forehead. "But—you have to have the power of the wall-switch—a power-plug to conceive life in your gravity box."

With, a jerk of his powerful hands, Halliday pulled the wires from the switch. At a motion Roy brought him a small dry battery. Holding the wires to the terminals, the inventor waited.

Again the sinister whisper rose from the plates in the box. It strained against Hardy's hands, floating in the air over the scientist's head.

"The box that Dr. Night took from here the night he stole my 'plane did not contain the secret he covets." Halliday spoke slowly. "That secret he unknowingly built into the 'plane itself. Yet, even if he knew where the secret lay, he could not duplicate it."

"Why not?" The inventor smiled "When you opened this box, what did you find? Merely a lining of queer-coloured plates joined by many wires. Take one of those plates; submit it to the best man you can find. He will ten you that he cannot name the metal. He cannot. It is from the earth; perhaps from the air. I alone know, and I reveal my secret when I deliver my 'plane into the hands of men honest and trustworthy, to deal with it for the good of all mankind."

"Is but the connecting link between the plates lodged in the wings, the body of the machine, and the tail. A generator worked by a small propeller gives electricity to that box, to excite the plates."

"But how is the machine propelled?" Hardy showed his perplexity. "I can understand those plates overcoming the power of gravitation and lifting the aeroplane. It then becomes an airship—lighter than air, at the mercy of innumerable air-currents."

"My machine is always heavier than air, when in flight," Halliday answered. "The power of gravity is not combated in one straight effort. The plates are so built that the gravity can be repelled or attracted at any angle. Therein lies the power of my speed."

Sir Max crossed the room with long, slow strides and stood before the inventor. Reverently his fingers touched the box, now resting on the table.

"My friend." A guttural sound came in the deep voice. "You have shown me and I believe. Men say I am rich, very rich. They tell me that when I touch a thing it rains gold into my coffers. Would they believe it if I told them I envied you, this?" Again he touched the box. "But I would be right. I envy you, Mr. Halliday."

Hardy nodded. He waited a full minute before he spoke. "I suggest you build a 'plane to Mr. Halliday's specifications, Sir Max," he said. "Not a small experimental 'plane like the one Dr. Night had constructed, but a real airliner—a machine that will carry many people and supplies for a very long voyage."

"Good!" The baronet nodded vigorously. "I have control of the Allanby aeroplane works. The plane will be started immediately—if Mr. Halliday will trust me with his invention."

For a long moment the two men looked eye into eye. Then the inventor extended his hand.

"I can trust you, Sir Max Vanderlere," he said, simply. "I will make the plates you require. The plans they are there." He pointed to a safe in the corner of the room.

"I shall not fall you." The baronet paused. "One thing I have to say. I will promise you no great wealth for your invention. First we must build and test. Secondly, we must discover and utterly destroy Dr. Night and the 'plane he stole. That accomplished, I will get the men who know and can plan. They will take your 'plane for the good of your country—the great Empire you and I and everyone who has sense believes in, and serves. I promise you that that Empire will deal with you justly and generously. Are you content?"

CHAPTER IX

IN spite of Sir Max Vanderlere's many appointments he stayed late in Halliday's laboratory, discussing the many phases of the building of the aeroplane to the inventor's specifications. When he left, Hardy joined Roy and the Hallidays at the evening meal. Again the conversation centred around the 'plane. Halliday was happy; at last he saw the fruition of his many dreams.

Roy was dog-tired when the journalist left for the city, and Ruth, with gentle authority, ordered him to bed. He found, however, that he could not sleep. For hours he lay awake, his brain busy on many, mostly inconsistent matters.

A clock chimed midnight and Roy threw back the covers and slid from the bed. He sipped at a glass of water, but it was tepid and lifeless. Not troubling to switch on the light, he went softly to the kitchen. He let the tap run tor some time then filled a glass and drank eagerly. The water refreshed him, yet he felt he could not sleep.

The house was wrapped in silence. Roy went to the window and peered out on the gardens. They were flooded with moonlight. Under the silver rays the brick laboratory was transformed to a house of beauty.

The grounds lay silent and deserted. Roy scanned the surroundings for the watchers Hardy had assured him were always on duty at night. He could see no one. Straining his eyes he searched every piece of shelter in the gardens, without result.

The laboratory appeared deserted, and within it lay a secret of untold importance. Had Hardy's plans failed? Had some mistake in orders delayed the men? For minutes Roy fumed and fretted in a paroxysm of indecision. At length, he decided that he would take up the watch himself.

He went back to his room and dressed, very awkward with his strapped shoulder and arm. Then going to the back door he opened it and stepped out into the shadows of the veranda.

A cane deck chair stood in the shadows, conveniently placed for him to watch the laboratory and most of the garden. Roy lay down and took out matches and cigarettes. Then he hesitated. If he was to watch, he should not smoke; the glowing tip of his cigarette might betray him.

He laughed. What could he do if he discovered some prowler about the place? With half his body in bandages he was not a match for a ten-year-old boy. His cigarette—a light—might be useful and frighten away any thief who did not know that behind the light was only a cripple.

A feeling of lazy contentment came over Roy as he lay back and smoked. His mind wandered in speculation of the adventures he believed lay before them. Sir Max would build a huge air-liner and in it Halliday, Hardy, and himself would hunt down the arch-criminal, Dr. Night. Perhaps the pursuit would take them far beyond the confines of Australia.

Hardy had spoken that afternoon of the Land of the Seven Rivers—Semarechensk he had called it. Hardy believed that in the heart of that secret plain stood some ages-old city, now deserted. Dr. Night claimed kingship over that city—possibly over the surrounding country.

That afternoon Hardy had told him of his strange dream. He had told them that he had thought he walked in spirit through deserted streets, bordered by houses of massive stone. He had come to the huge central square where stood the towering temple of the city's gods. He had spoken of the great throne reared in the centre of the square, and Dr. Night seated on it, splendid in royal robes and wearing on his forehead the Green Pearl, ancient emblem of his house.

The Green Pearl! Roy remembered reading of that remarkable gem some couple of years previous. It had been an article in an English magazine and, peculiarly, spoke of the jewel's many adventures. The article had been written by a certain Captain Therrold and recounted his adventures in Soviet Russia when he went to recover the gem for its rightful owner, the Grand Duke Paul Therrold had succeeded in his quest, but in his escape from the Soviet agents had been driven right across Asia to Australia. In the latter country he had met with many strange adventures but had succeeded in retaining the Green Pearl; conveying it to London and its owner.

Dr. Night had vowed to obtain possession of the Green Pearl. He had openly stated that without it he could not draw together the scattered tribes of Semarechensk and weld them into a kingdom. Had Dr. Night succeeded in obtaining the Green Pearl—during the many months he had been absent from Australia?

Roy found himself nodding drowsily. He pulled himself together with a jerk. That would not do! He stood up and stretched himself.

Something was moving in the garden. Only a brief movement and then the stillness again. Now all thoughts of sleep were driven from him. He was awake, keen, alert. He moved to the edge of the veranda, partially concealed by one of the posts, and waited.

Almost he believed that he had been mistaken. For long minutes he searched the moon-drenched gardens. From where he stood the door of the laboratory was in plain sight; the moonlight falling full upon it.

Roy turned back to his chair, then hesitated. Why should he not stroll around the grounds; go to the laboratory door. He was now alert to catch some marauder. In his crippled condition that would be impossible. He was watching that his known presence might drive any thief away.

He stepped down on to the garden path and strolled around the house to the front garden. For some minutes he stood at the gate watching up and down the road. There was no one in sight. A careful look around the borders and shrubbery and he returned to the rear of the house.

As he turned the angle of the house he halted, abruptly. Something, someone, had moved in the little patch of bush to the right of the laboratory. With high beating heart, Roy sauntered down to the spot. Again he could find no intruder.

He went to the laboratory door, taking care not to touch it, for Halliday had told him that the door and windows were protected by many strange devices.

The door was fastened and appeared intact. Roy skirted the building, peering in at the windows. He could find nothing outwards; yet his strange uneasiness persisted.

Where were the police watchers? Again Roy searched the gardens, and again without result. In sudden resolution he returned to the house. In his room he looked at his watch It was ten minutes to one in the morning. Hardy would have seen the first editions off the machines and would be preparing to hand over to the night-editor.

Should he ring him up and tell him of the strange uneasiness that possessed him? Why not? Hardy would understand. Perhaps a short talk with the chief sub. would steady his nerves and then he could return to bed—and sleep.

Roy stood in his room, considering what he should do. The telephone was in the hall. If he used it the slight sounds might awaken Halliday or one of his family. He did not want them to know that he was prowling house and gardens; prey to a strange uneasiness he could not control or explain.

He snatched a blanket from the bed and crept into the hall. Smothering the machine with the blanket he lifted the receiver from the hook, allowing it to dangle to the end of the cord. Then, pressing his sound shoulder against the blanket to keep It In place, he dialled the Mirror's number.

Now he-had to work his head and shoulders under the blanket and still keep it covering the machine—and that with one available hand. At length he managed to accomplish this, continually calling to the switch -girl to hold the connection.

"Bob Hardy there?" he called, at length. "Bob Hardy! Roy Iston here. Are you there. Bob Hardy? Roy Iston."

"Something's up here." Roy spoke in a whisper. "Something's going to happen. I'm certain of it. No, don't call me a fool, Bob. I've got a hunch. There is something going to happen."

"Stop rotting, man. I tell you there's trouble looming. I've seen nothing definite yet, except moving shadows in the garden—"

"I've tried to—and he doesn't answer. Look here, Hardy. Pick up someone at Police Headquarters and get out here as quickly as possible. Something's up, I'll swear!"

Hoy carefully unwound the blanket from the Instrument and carried it into his room.

For more than a minute he debated his best line of action. To watch the laboratory door seemed Indicated, for there was the main point of attack. He went again to the back veranda and scanned the grounds. All appeared quiet and peaceful. He stepped down on the path and went down to the building.

Turning a bank of greenery he came in full sight of the laboratory door. Something dark lay before it. A moment's hesitation and he broke into a run.

A man lay on his face before the door, his left arm crumpled under him in a strange, limp fashion. Roy bent over him, but could not catch a glimpse of his face. Then he noticed that in the man's right hand was gripped a large automatic.

CHAPTER X

"WHAT'S the matter, Roy?" Hardy and Inspector Frost had come round the side of the house and stood beside the prostrate man. "Who's this?"

"I don't know." Roy rose to his feet. "I've been restless ever since you left here last night, Hardy. I couldn't sleep, thinking that someone was prowling about the place. I came down here to see that the laboratory was all right—and found him."

"Not a soul. I thought I saw someone moving in the shadows, once or twice, but then fancied that I had been mistaken. I looked for your man, Inspector, but he was nowhere about."

"Matthews!" The Inspector looked up from his examination of the dead man. "He should have been here a long time ago."

He put his fingers to his lips and blew a low, sweet, penetrating note. There was no reply. Roy looked at Hardy and shook his head.

"Twice. I did as you told me. Went to the front gate and held my handkerchief over the top. But no one came."

"No." The detective stood up and flashed the light of his torch on the white face. "No man who was shot ever looked like that."

The three men looked down on the still dark form, the blanched face from which the still eyes stared upwards; holding In their depths the shadow of some frightful, terrorising death. The lips were drawn back, baring tobacco-stained teeth, in a grimace. On one of the ill-shaven cheeks were five round marks, each about the size of a three-penny piece.

"Can you use the 'phone without waking up the household?" asked Frost, suddenly.

"Can try. I managed to call Hardy." Roy laughed slightly at the remembrance of his struggles under the blanket.

"Whew!" The newspaper-man paused. "So you think this bird put Matthews out of the way and then—

"Just so." Frost moved away from the laboratory door. "No need to watch him. He'll be there when we return. As you hint, Hardy; Dr. Night."

The detective commenced a methodical search of the grounds. He had not proceeded far when he came to a patch of low shrubs. He halted, with a low exclamation. From under a low-hanging bush protruded a pair of legs.

"Matthews, for a million!" With gentle hands he caught at the legs and, with Hardy's help, drew the man from under the bush. A moment and he stood up. "Not dead, thank goodness. But, he's had a brute of a welt over the head."

For some minutes they worked over the man. Once Hardy paused to answer Roy's whistle directing him to where they were. The reporter exclaimed when he saw the insensible man.

"Dr Night, we suspect to the first question," replied Hardy "Matthews, to the second. Where's that doctor?"

"Coming. Dr. Carlton, he calls himself." The journalist bent and examined the severe wound that stretched across the crown, from the forehead. "Jove someone hit with intent that time."

Frost nodded. His exertions had succeeded in bringing the man to consciousness. Matthews opened his eyes and strove to sit up. The detective took his flask from the ground and poured some raw spirits down the man's throat.

"Didn't see." The man made a long pause. "I thought I saw someone in here and came to search. Then I was struck from behind and went out. I never saw who struck me."

"No." Again the man paused. "Is he here? Did he hit me? I'll get him for that, if—" He closed his eyes. "Suppose that was to pay me out. for the Lewisham Bank affair."

"Sam 'ud never die in his bed." The detective spoke with closed eyes. "There's more than two or three in Sydney who'd be glad to put him on the spot."

"Don't know Ah. here's the doctor."' The Inspector rose to his feet and walked across the lawn to the read gate.

For some minutes the detective and doctor stood talking earnestly; once or twice Frost glancing round at the house At length they came to where Matthews lay. For a quarter of an hour the doctor worked over him, washing his wounds and bandaging them. He stood up and turned to Frost.

"He'll do now. Get him home to bed. A couple of days' rest and he'll be fit again, though his hat won't sit comfortably on his head. You say there's another injured man here. Where is he?"

"He's dead; by the laboratory door." Frost led the way. "All you can do for him is to tell me how he died."

"Strange!" he muttered. "From the look on his face one would think he died from strangulation, but there are no marks on his throat."

For long minutes Dr. Carlton bent over the corpse. At his request, Frost illuminated the marks with the light from his torch. At length he nodded, as if satisfied. He turned to Hardy and placed the tips of his fingers on his cheek, pressing hard. He caught the torch from the detective's hand and focussed the light on the newspaper-man's face. Five little angry-looking marks showed on the white flesh.

"But no man's fingers impressed on a man's face ever killed him," expostulated Frost.

"Never said they would." Dr. Carlton, a short, stubby man, laughed. "All I did was to show you how those marks were made. I'm not a Sherlock Holmes. It's for you people to draw your own conclusions. Want me any more?"

"No, thanks, doctor. You'll give the necessary certificate, of course. By the way, you're going home? Thought so. Will you please, ring up Police Headquarters and tell them to send out the ambulance and a couple of my men. Speak in my name—Inspector Frost. I don't want to ring from this house containing a couple of women and a crippled man."

"Whose house?" Dr. Carlton paused. "A crippled man? Oh, of course. Lieutenant Halliday, isn't it? Lost his legs in the war? Thought I knew the place, though I've never met him. Well, goodnight, Inspector. Good-night, gentlemen."

The little doctor ambled across the lawns and disappeared around the side of the house. For some moments the four men stood without speaking. Suddenly, Frost turned to Matthews.

"Feel all right, now? Good. Our car's down the road a few yards. Can you make them? Right-o! Get along and rest in it. We'll take you home when we've finished here." He waited until the detective was out of sight, then turned to Roy. "All right, inside?" He nodded towards the house.

"Know Halliday's room?" When Roy nodded, Frost continued. "Think you can wake him without alarming the women-folk?"

Frost nodded towards the house. "Get him out on the veranda. We'll come and talk to him there."

Roy went to the house. In the hall he paused and surveyed the doors. He knew which was Halliday's room and listened at the panel.

He could hear no sounds within the room. A moment's hesitation and he turned the handle and pushed open the door. There was no light in the room. Feeling cautiously before him, he stole to where the bed loomed in the shadows.

He tried to peer down on the pillows—to see the inventor's head, but could distinguish nothing. He felt with delicate touch over the covers, trying to locate the inventor's body. He was not there. In sudden terror, Roy sprang across the room and switched on the lights.

CHAPTER XI

FOR some moments Roy stood surveying the room. The bed had been slept in; the covers were thrown back in disorder. Halliday's clothes were missing and also the wheeled chair, which usually stood during the night beside the inventor's bed.

Then, the inventor had risen from his bed and gone out of the room. To where? Roy walked out into the hall. The next room was occupied by Mrs. Halliday. Was he there? Somehow, Roy did not think that probable.

The two remaining rooms opening from the hall were, occupied by Ruth—and the room he was occupying. He opened the door and glanced into the room he occupied. No one was there. He listened at Mrs. Halliday's door and could not hear a sound within.

Moving silently, he went out on the back veranda. There he found Hardy, and the Inspector. They looked at him expectantly. He beckoned, and led to the Inventor's bedroom. No words were needed to explain the situation. While Hardy and Roy remained by the door Frost made a rapid search of the room. In a few minutes he rejoined them.

"Halliday got out of bed about an hour after he entered it," the detective muttered. "He dressed and entered his wheeled chair. From there—"

He threw the light of his torch on the linoleum and tip-toed up the hall. For some moments he stood before the front-door, then he returned to the newspaper-men.

"Didn't go out of the front door," he whispered. Then, after a pause. "What time did he go to bed, Iston?"

"Hardy and Sir Max left the house about half-past ten," Roy replied. "Half to three-quarters of an hour later Mrs Halliday and Ruth retired. Halliday and I followed about ten minutes later."

"Then Halliday was in bed about eleven to a quarter past. You say you got up about midnight. What did you do when you went to bed?"

"Yes, rather." Roy hesitated between the words. "Yes, I awoke quite suddenly. In fact, I don't remember anything before finding myself standing by the bed."

"Perhaps we can find out." Frost led on to the veranda. For a few minutes he walked up and down, then went down the slope to the lawn. Something he found there satisfied him, for he nodded several times, then beckoned the newspaper-men to him.

A man came round the corner of the house on to the lawn. The Inspector went to him and they exchanged a few words. The man went back towards the road, returning in a few minutes with two companions. Frost beckoned and led down to the laboratory.

When they came within sight of the door, Roy gave a little gasp and clutched Hardy's arm. Frost stopped dead, tilting his hat forward and scratching the back of his head.

The dead man had disappeared. Where he had lain in the moonlight was a bare patch of gravel.

The sounds from a motor engine coming suddenly to action attracted their attention. Without a word Hardy dashed across the lawns around the corner of the house to the roadway.

A car was moving from before the gate. Frost ran on, tugging at his hip pocket. As he passed through the gate he shouted a command for the car to halt. Either the men in it did not hear him or Ignored his order. The car drove on, gathering speed.

The Inspector ran down the road to where the car in which he and Hardy had come to Vaucluse stood. He leaped in and started the engine. When the car moved, it bumped on the macadamised road badly.

"Damn!" Frost drew up with a jerk. He leaned over to the back seat and shook Matthews roughly. "Who's been at this car?"

The plain-clothes man mumbled something, dazed by his sudden awakening. Frost did not wait to repeat his question. He jumped out and ran to the back of the car. The rear tyres had been heavily slashed with a knife.

Leaving the car with the now wide-awake Matthews, Frost went into the Halliday gardens and joined the newspaper-men.

"Someone took Rothsay's body away in a motor-car," he explained shortly. "Can't be helped. Now we've got to find Halliday."

A short search and he again came to the laboratory door. As he lifted his hand to the latch, Roy intervened. "Careful, Frost!" he exclaimed. "Halliday told me that anyone that tried that door without his sanction would get a baa shock."

He ran back to the house, to Halliday's room. Close to the head of the bed he found what he was looking for—an electrical switch. But—it was open! What did that mean? For a moment he was puzzled, then went out of the room and closed the door.

He knew that Halliday protected his laboratory by some electrical contrivance. The inventor had been particular never to go into the laboratory unless the door stood open. But was the place protected now? The open switch suggested not.

Halliday was missing and the laboratory was unprotected. Roy shrugged, as he crossed the lawns to rejoin his companions.

Roy did not answer. He passed the two men and went to the door. For a moment he hesitated, then caught the handle and pushed the door open. The laboratory was in darkness. The three men crowded to the doorway, peering in, but they could see nothing. Roy reached round the lintel, feeling for the switch. He pressed in the little knob and the great globe in the centre of the ceiling burst into life.

"Look!" Hardy caught at Roy's sore arm, but in the excitement of the moment the reporter did not feel the pain.

Seated in his wheeled chair, beside the table on which the globe stood, was Adam Halliday. His eyes were open, staring fixedly at the door; but he gave no signs that he had seen the three men enter. Frost crossed the room quickly, and bent over the inventor.

"All right!" he nodded, briefly. "Either drugged or—or some other devilment of that heathen Chinese. Look!" He pressed his finger on one of the staring eyeballs without the man flinching.

"For all that we know he may be here now." Frost looked inquisitively around the big room. "Lor', what a man!"

"What's this?" Roy picked up a piece of paper, lying beside the globe. "Why—" He stood staring at the paper, his mouth fallen open. Hardy snatched it from his hand. "Listen, Frost. This is a receipt from Dr. Night for the plans of Halliday's mystery 'plane. The damned cheek of the man!"

The Inspector did not answer. He was bending over Halliday. Roy went to his side.

"No good." Frost spoke, gruffly. "The man's mesmerised. I can do as much good as any doctor."

For ever an hour the three men worked on the inventor. At length a change came on his fixed features. He sighed once or twice and shut his eyes.

"What's the matter?" He looked around the laboratory. "Why—why am I here? I went to bed, didn't I?"

"And got up again," Frost laughed shortly. "Don't von remember anything more, man?"

"I had a dream-a strange dream." The cripple rubbed his eyes with his hands. "I thought Dr. Night—"

"I thought he came to my room and told me to get up and go with him He helped me dress and put me in my wheeled chair. We came down here."

"There was a man standing before the laboratory door. He stepped aside and watched me open it. Dr. Night pushed me inside and the man caught at his arm."

"I thought they quarrelled. Then Dr. Night said something in a voice that made me shiver. Almost immediately he came and joined me."

"He wanted the plans of the aeroplane. I refused to give them to him. He became angry and insisted. Then, suddenly, he commanded me to be silent. I heard footsteps outside the building and went to cry out but Dr. Night placed his finger on my lips and I could not."

"Again he asked for the plans. I could only shake my head. He commanded me to tell him where the plans were. They were in the safe." Halliday pointed to ft corner. "He asked for the safe combination, and I gave it to him. He went to the safe and got the plans out."

"He used a torch giving a small, thin, yet powerful light—and the blinds were drawn on the windows," Halliday explained.

"I must have." The inventor stared at the paper, bewilderedly. "But I don't remember it."

"The point is that now Dr. Night has the plans of the new aeroplane." Hardy showed his disappointment. "He's beaten us all along the line."

"What does it matter?" Hardy interjected. "Dr. Night had you under his influence. It is only reasonable to believe he asked you for the formulae—and you gave it to him."

For a long minute there was silence In the room. Then, from the gardens came a woman's shriek.

"God! That was Ruth!" Roy dashed to the door. Disappearing round the corner of the house was a man bearing in his arms the form of a woman.

CHAPTER XII

BAFFLED and outwitted, Hardy and Frost returned to Sydney. Roy accompanied them. He could not bear to stay at the Halliday's home and witness their grief at the loss of their daughter. He had spoke brave words of hope—of a quick restoration of the grave, blue-eyed girl who, in the few days of their association, had come to mean so much to him.

In his heart, Roy vowed that he would not rest until he had rescued Ruth from the clutches of the Asian. His silent vow seemed to bind him more closely to Hardy. The sub-editor, in past days, had suffered a similar bereavement at the hands of Dr. Night. The memory of those days still lingered in Hardy's mind and drew his sympathy to Roy.

The newspaper-men dropped Matthews and Frost at their respective homes and then Hardy took Roy to his home. The reporter, was grateful for the thought. His relations were in the country and he could not think of his lonely diggings without a shudder.

"Holmhurst," where Mr. and Mrs. Hardy lived with her father, Henry Blayde, was in darkness when Hardy turned in at the big gates and drove up to the garage. They housed the big car and then the chief sub. showed Roy to a guest-room. At the door he lingered a moment.

"Keep a stiff lip, Roy." Bob Hardy did not look at the young man as he spoke. "Dr. Night's not so bad, y'know. He treated Doris decently, although he kept her under lock and key. He'll just hold Ruth until—"

"The devil!" Roy swung on his heels and went to the window. "Why can't he fight men? A woman—a girl—"

Roy stood before the windows for some time, trying to form plans for Ruth's release from the Asian. Schemes, fantastic and unreal, flashed across his mind, but even the most probable rested on a knowledge of Dr. Night's headquarters. He took to pacing the floor, then suddenly flung himself on the bed and buried his face in the pillows.

Sleep overcame him—a long, dreamless sleep that lasted well towards midday. Twice Hardy looked in on him and went away again, content to let his friend sleep his fill. The third time he entered the room and shook the reporter by the shoulder.

"Just on noon." Hardy spoke cheerily. "Thought you'd like to know that I've had a 'phone call from the chief. He wants me down at Phillip Street as soon as possible."

"That's why I roused you," Hardy grinned. "Thought you wouldn't like to be out of any happenings. No need for great hurry, young fellow. I've put razors, etc., on the dressing-table; the bath's through that door. The' missus is having breakfast sent up so that you can feed while you're dressing."

"Some people call me 'Bob.' Doris say it's vulgar, but nice. As to the tray, just one of the house-boss' little peculiarities. She will insist of feeding all and sundry who crosses her threshold—even so insignificant a thing as a husband."

He shut the door and went downstairs, whistling. In a few minutes a maid brought a breakfast tray. Much to his surprise, the newspaper-man found that grief could partly be assuaged by food, especially when the last meal was many hours back.

The sounds of a motor-horn honking from the driveway took Roy to the window. Hardy was in the car, calling him. He waved his hand and raced down the stairs. On the hall-steps he found Doris Hardy, looking little older, if a bit more matronly, than in the days when she had loyally backed Bob Hardy in his fight against Dr. Night and the drug-ring he controlled. "Roy stammered his thanks for her hospitality.

"But you're only leaving us temporarily," Doris laughed. "You are coming home with Bob to-night. You know your room, and that stay-out-late husband of mine will find you a latchkey."

"But—er-Bob." The girl laid her hand on his arm. "Bob woke me this morning and told me about—about it all. I'm sorry—but—but it will all come right in the end. The Princess always escapes, the dangers and-"

"Leave Roy alone, woman." Hardy was standing at the foot of the steps. "For my sins I am married to a wife who cannot leave other men alone. Why, if I hadn't interfered. I believe she would be to-day Mrs. Dr. Night, instead of—"

"He had nice grey eyes," Doris spoke dreamily. "I always said I would never marry a man with brown eyes. They're so awfully jealous."

"You had to marry one to find that out, lady," Bob laughed. "Come on, Roy. Thomas will be tearing, the office to pieces if we delay longer."

Alphonse Thomas was striding up and down the big reporters' room when Roy and Hardy entered.

"So there you are, at last—and, of course, not a line in the paper about Dr. Night. Do you fellows think this is a charity organisation for decrepit journalists? Robert Hardy, with your—"

"The affair happened too late for the last edition, sir." The chief sub. was in no way disturbed by the managing editor's apparent temper. "I've got plenty for tonight, and it'll be a scoop."

"And I've got plenty, too." Thomas strode into his room and snatched up a letter from his desk. "Read that! Of all the damned impertinences."

Hardy took the letter, a typewritten document. The paper was of common quality. He did not examine the type. Dr. Night would not leave traces. Roy looked over his shoulder and gave an ejaculation of surprise; then read aloud:

"I am in urgent need of the sum of £500,000 for the payment of a debt I have incurred. As it is necessary for me to leave Australia very shortly, never to return, I shall be grateful if my many business friends in Sydney will assist me to honour my obligations.

"From the rich and generous of your city I have chosen the following gentlemen to contribute to my necessity. I ask you to inform them of their selection."

Then followed a list of twenty names. Every man selected was known for his wealth.

"I am sure," continued Dr. Night's letter, "that these gentlemen will not refuse my request. I write no threats; except that my necessity knows no law. I should regret, exceedingly, to have to be insistent."

The letter was signed "Dr. Night" in typescript. For some seconds after Roy ceased reading the three men were silent.

"'Course he does." The managing editor was impatient. "What am I to do with it?"

"And to be laughed at as a ruddy fool!" Thomas showed his irritation. "If I took that letter to any one of them they would send for the police."

"Perhaps that is the best solution." Hardy turned to the telephone and put through an urgent call for Inspector Frost.

"There's many men's names missing," the managing editor snapped. "Of whom are you thinking?"

"Sir Max Vanderlere," The reporter paused. "Then Simon Cohen isn't in this list, nor Bertram Upton."

"Rather a rough thing to say." The reporter hesitated again. "Sir Max, Cohen, and Upton are noted for their unassuming generosity. Much of their great wealth they devote to public causes. The men indicated here—"

Thomas snatched the list from Roy's' hands. He read down the list of names again and laughed.

"Your friend, Dr. Night, has made a bloomer in this." He turned to Hardy. "This list is of the twenty hardest nuts in the Commonwealth. Why, to get money out of one of these would be like wringing water out of a stone."

Hardy nodded. Roy's conclusion had not been lost on him. Dr. Night had acted to his queer psychology. He could have chosen twenty men from Sydney's wealthy population who would have proved easier prey. Instead he had selected men who worshipped money as their god; men who gave nothing without great interest in return; men whose sole interest was centred on self.

"More trouble?" The inspector had entered the managing editor's room unperceived and had overheard Thomas's remark. He took the letter the managing editor extended to him and read it rapidly.

"If you went to them and showed them that letter they would accuse you of attempting blackmail."

"Publish it," Roy suggested. "As a news item it will go over big. They can't object to that, and if they don't take the warning that's their funeral."

Frost laughed. "'Fraid the Police Department can't subscribe to that theory. We've got to protect them from the scoundrel. Still, publishing that letter will do no harm. More than likely one or two of them will get the willies and ask our protection."

"With the story of last night's happenings it will make a fine front-page scoop," exclaimed Roy.

Thomas looked at the reporter inquiringly. In brief, graphic sentences Roy sketched the happenings of the previous night. The managing editor's eyes beamed. Here, indeed, was a big story.

"How's Dr. Night going to deal with these fellows?" The inspector was bending over the telephone directory. "Will he take them in order or haphazard?"

"It'll take half the department to guard that lot." Frost referred to the directory again. "Look here. First on the list is Warrington Smayles. He lives at Mosman. Then comes Leverel; his place is somewhere out Bondi way. Third man is Manning Forbes, and he motors into town from Moss Vale every morning. Of all the puzzles—"

"And bleeds the first two or three," the inspector laughed. "No thanks, Roy, someone would be demanding my head on a charger if I went to work that way."

"Anyway, we publish that," decided Thomas, tapping the letter. "Now, while the inspector is here, we may as well decide which and what of last night's happenings is to be included in the news."

For over an hour the three men discussed the defence against Dr. Night's attack on Sydney's business, and how far the general public was to be informed of the master-criminal's activities. An agreement arrived at, Roy was, to his great satisfaction, deputed to write the story.

The next morning the Mirror announced to a puzzled Australia that Dr. Night had returned.

RANSOM.

Dr. Night Blackmails Leading Citizens.

Mystery at a Vaucluse House.

A Dead Man Disappears.

Where Is the Silent Mystery 'Plane?

CHAPTER XIII

THE Mirror's account of Dr. Night's bold threat to blackmail twenty of Sydney's leading business men caused a great sensation the next morning. The newspaper's telephones were kept busy, but Alphonse Thomas had given orders that no inquiries on the subject were to be answered. The matter, with all documents that had been in the possession of the newspaper, was now in the hands of the police.

During the morning Frost made a journey to Vaucluse, and again carefully examined the gardens and the laboratory. Halliday had had no news of his missing daughter. No demand for ransom had come from Dr. Night.

Shortly after midday the Inspector went up to the Mirror's editorial offices. He had only been conferring with Thomas for a few minutes when Hardy and Roy were summoned.

The call was a relief to the young journalist. He had wandered aimlessly about the big building, unable to settle to any definite occupation. Twice he had telephoned the Hallidays to be informed that there was no news of Ruth. Mrs. Halliday was prostrate-Halliday had locked himself in his laboratory, refusing to see anyone.

"Sit down," Thomas spoke abruptly. "Frost wants to consult you. What's to be done?"

"Easier said than done," the Inspector laughed heartily. "I'd give a month's pay to get a lead."

"Dr. Night will provide that presently." Hardy appeared to be the most composed member of the party, but his restless fingers betrayed the stress under which he laboured.

"It's hell for me," Frost exclaimed. "I came across here for a little relief. Do you realise that each of those twenty men named in Dr. Night's letter have applied for police protection? The Commissioner—well, a bear with a sore head is a lap-dog in comparison to him."

"None. We've created a certain calm by talking of bluff and the impossibility of there being such a person as Dr. Night. Stated the whole affair is only newspaper stuff."

"They've got to take it." Frost struck his fist on the desk. "We've got to assume there's no such person—until he makes his first move."

The shrill ring of the telephone bell prevented an answer. Thomas lifted the receiver, spoke a few words, and then shifted, the instrument across the desk to the Inspector.

The Inspector lifted the receiver and listened, his face growing dark. He replaced the receiver with a jerk and thrust the instrument from him.

"Hofton Wales is with the Commissioner," the detective grinned. "Says he's received a letter from Dr. Night. He asks for £10,000 immediately."

"How, and where?" Thomas interjected. "Don't know. I'll tell you when I have interviewed the gentleman." Frost went to the door and hesitated. "Say, Roy, you come with me. I may have to go out when I've interviewed Wales. You can come back and tell our friends the glad tidings-"

"Wait a moment, Frost," exclaimed Hardy. "How about letting Roy hang round your office all the time. He's keen and reliable. You may want help, and, with twenty men to guard—well, even a journalist may fit in."

Frost laughed and nodded. Roy sprang to the door and returned, hat in hand. Together they went to the elevators.

"Financier, company promoter, investor. Take your choice," the Inspector laughed. "Wonder why Dr. Night chose him? He's the poorest of the twenty, by all accounts."

"Which he won't get." The detective hesitated. "No, Wales is out for his own hand. He's not giving anything away. Wait a moment."

They were on the pavement before the Mirror offices. The Inspector took a newspaper from his pocket.

"Thought so," he continued. "Third on list. That settles it. If Wales had headed the list we might have had a chance."

"Hofton Wales will not part with a bean." The detective explained. "If he had been first on the list there was a chance that number two would next receive Dr. Night's attention."

They were on the steps leading up to Police Headquarters. Frost shrugged his shoulders and led down the corridor to his office.

Alone, Roy paced the small office. Again the trail had opened before them. Would it lead them to a new impasse—or to Dr. Night? Where he found the Asian he was certain he would find Ruth. An overwhelming impatience seized him. Why was he loitering around the Mirror offices and Police Headquarters when his girl was in the hands of that fiend?

Suddenly the door opened and Frost came into the room, accompanied by a medium-height, stout young man, with an unhealthy, florid face. The small light-blue eyes, were hard and selfish.

"Now, let's have that tale again. Mr. Wales," suggested the Inspector, when they were seated Then, noticing the suspicious glances the man cast at Roy, he laughed. "Mr. Wales, my assistant. Roy Iston. Take my word for it Mr. Wales, Roy's safe."

"Oh—all right. Yes." Wales appeared to be relieved. "Well, you know it all by now, don't you?"

"Can't have too many repetitions," Frost laughed. "Let me put Roy wise. You are Herbert Hofton Wales. On the rolls you are described as a financier. That's to say, a money-lender. Registered?"

"No!" The detective's tone was almost offensive. "You've done a bit, of company promoting. Mr. Wales?"

"What's that got to do with it?" Wales flushed, angrily. "Yes, I've got a wife and boy ten years old."

"Good. You say you received a letter from someone signing himself 'Dr. Night.' Where?"

"I came as soon as I got the letter. I did not leave home until midday and went straight to my club, where I had a luncheon appointment."

"From your club you went to your office, where you found awaiting you a letter from Dr. Night?"

"I rang up the Police Commissioner and told him of the letter. He asked me to bring it to him at once."

"Here." The Inspector shoved a letter across the desk towards the newspaperman. Roy seized it and read the single page, eagerly.

Dear Mr. Hofton Wales,—

You have no doubt seen the article in the Mirror this morning containing my letter to the editor. That letter contains a list of twenty leading citizens of this city. Your name stands third on that list.

I expect each of you twenty gentlemen to contribute according to your means to a fund in which I am interested—a fund to adequately reward a man who deserves well of his country. I have not the slightest doubt but that you will accede to my wishes.

If, however, you should, through press of business, put my letter on one side and forget it, I can assure you I shall have, very reluctantly, to forcibly bring it back again to your memory—by taking from you something you hold very dear.

The sum I value your contribution at is £10,000. You will immediately obtain that sum from your bank. Later you will be instructed how to convey your contribution to me.

—Dr. Night.

Roy read the letter aloud. When he concluded he looked up. The Inspector had a broad smile on his face; Wales was frowning, his face red and set.

"Obtain that money to-day." The Inspector mused. "Am I to take it, Mr Wales, that the money is at this moment in your office safe?"

"You are not." The man started from his chair in sudden fury. "Do you think I give my money to anyone who chooses to threaten me?"

"'By taking from you something you hold dear.'" Frost quoted from the letter. "What is it that you hold dear. Mr Wales?"

For a moment the financier did not answer, then: "A man in my position owns many things of value."

"You say you have not drawn the £10,000 from the bank, Mr. Wales?" continued the Inspector.

"It is now twenty minutes to three. You have time to reconsider your decision, Mr. Wales."

"It is your duty to protect me," Wales spoke arrogantly. "What do you think I pay rates and taxes for? I expect protection."

"You have it." There was a grim note in the Inspector's voice. "Immediately your name was mentioned as the future recipient of Dr. Night's attentions, men were sent to guard your home and office. The police can do no more, Mr. Wales. It is a pity you cannot take some steps for your own protection."

"You will immediately obtain that sum from your bank." For the third time Frost quoted from Dr. Night's letter. "You fool, don't you see that you have let slip one good chance for us to capture this criminal. If you had taken that money from your bank Dr. Night would have had to come forward to receive it. There was our big chance—and you have let it slip through your carelessness."

Without a word Wales stood up, thoroughly cowed by the Inspector's anger and went to the door. As his hand touched the handle, the Inspector spoke, sharply.

"Where are you going, Mr. Wales? The bank will be closed before you get outside this building."

"Good. Go home and guard your greatest treasure. I tell you, Hofton Wales, Dr. Night never promises more than he can perform."

The door closed on the financier. For some moments Frost sat in deep thought. Suddenly he looked up.

"We will give him an hour. Lunched yet, Roy? No. Neither have I. It's late, but there's eats left, somewhere. Come along!"

Three-quarters of an hour later they returned to Inspector Frost's office. Hardly were they seated before the telephone bell' ran.

"Wales. Hofton Wales, speaking!" The voice was almost a shout. "For God's sake, Frost, come over at once. My boy—my son—has disappeared."

CHAPTER XIV

THE police car was at the door, waiting. Inspector Frost motioned Roy to enter and followed. In silence they waited until the car drew up at the end of the long queue awaiting the punt for North Shore.

"Something like it." Frost smiled, grimly. "Do you remember the wording of Dr. Night's letter: 'by taking from you something you hold very dear'. There was hardly a choice. Wales holds his money dear—and his son. He refused to part with his money, so—" He shrugged.

"I'd thought of that." The Inspector laughed aloud. "Shows you've not read your own paper too carefully. Twice Mr. and Mrs. Wales have made their domestic dissensions public. So—nothing doing there."

"But, surely—" Roy hesitated. "If you had that suspicion, why not have taken precautions?"

"How?" A harsh note rang in Frost's voice. "What chance did Hofton Wales give me? I know he lied when he told me he did not get that note until after lunch. He was seen to enter his office soon after ten o'clock. No, he, at first, determined to ignore it."

"He changed it during the lunch-hour. You know how everyone is talking of Dr. Night and his big demands. Possibly Wales lunched with a party discussing the subject. He may have mentioned that he had received a letter. His friends would certainly persuade him to go to the police."

"If you suspected that Dr. Night would strike in that direction—at the child: could you not have taken precautions there?" Roy protested.

"I did what I could, but Wales deliberately hampered me. You heard Dr. Night's proposals. The money was to be withdrawn within five hours. Of those Wales wasted four. Do you imagine that Dr. Night did not have that man watched; that he knew that he had not obtained the money, and that he had come to Police Headquarters? Of course, he did. He waited until three o'clock and the banks were shut. Then he struck."

"But—you would not have had Wales pay over the money?" the newspaper-man exclaimed.

"No; but I wanted time." Frost frowned. "The only way Wales could gain time for me was by withdrawing the money. Dr. Night would have learned of that. He would have then to advise Wales how he was to dispose of the cash. That would have given us eighteen hours, at least, to make our plans.",

Roy nodded. Now he understood the note. Dr. Night had taken all precautions, and, guessing at Wales's probable actions, had used them to his purpose.

From the first Roy had wondered why Dr. Night had asked for so small a sum as £10,000 from Hofton Wales. In proportion to that sum not half the half a million demanded would be raised from the twenty men listed. So, Dr. Night had anticipated refusals and evasions. What would be his next move? One thing Roy considered certain. A far larger sum than £10,000 would be demanded for the return of the child.

Against the theory that he was constructing Roy had to place the fact that Hofton Wales was by far the poorest of the twenty men listed. What would be Dr. Night's next move in the game? Would he choose the poorest of the remaining nineteen for his next victim That seemed probable. He put the point to the Inspector.

"Very likely," Frost nodded.. He pulled a list of the twenty men from his pocket. "Let's consider. Here's Britton Chambers, Albert Wilson, and Paul Lefevre; all about the same financial rating. Which of the three will he choose?"

"Give it up." Frost laughed shortly. "Anyway, you've scored a big point, Roy. I'm going to concentrate my men on those three probable victims. Same time, we must remember Dr. Night likes to do the unexpected; he may hit next at one of the big dogs. Well, we'll have to risk that. I can't keep proper tabs on nineteen men all fiercely resenting the slightest curtailment of their liberty and still carry on the hunt for Wales's son."

"Lor'! Let him pull off a couple more of these stunts and there won't be enough men in the Police Department to carry on the hunt."

The police car swung in at a pair of very ornate gates and drew up before a tall portico. Hardly had it come to a stop before a woman darted out of the house and precipitated herself on the Inspector.

"There, there, ma'am." The Inspector spoke awkwardly. "We'll do our best, you may be sure. There's no cause to fret—"

"That's the way we get police protection." Wales stood on the top step trembling with rage. "Our money—"

"Damn your money!" The woman turned on him, furiously. "You save your money and I lose my boy!"

"Stop this bickering, both of you, and tell me how the boy was lost." Frost spoke impatiently.

For some time he had to argue and persuade, then he succeeded in obtaining something like a coherent story from the antagonistic parents.

Herbert Wales, junior, had left for St. Anthony's College at his usual time that morning. He was to have lunch at the college and to return home about four o'clock. At that time Mrs. Wales knew nothing about Dr. Night's demands on her husband's banking account nor the threat accompanying that demand.

Wales had driven home direct from Police Headquarters, and, immediately on entering the house, had demanded his son. Mrs. Wales had replied that Herbert was not due home from college for at least another half-hour. They had waited for the lad's arrival. Incautiously, Wales had allowed his wife to learn of Dr. Night's demand and threat, and she had staged a scene of violent hysterics.

The time came and passed for the boy to arrive home and there were no signs of him. Mrs. Wales had insisted that her husband immediately inform the police.

"Then you don't know whether he is abducted or not?" Frost ejaculated, in deep disgust. He pulled out his watch. "Why, it's only a quarter to five now. He may turn up any minute."

"He won't! He won't!" Agatha Wales moaned, throwing herself on the couch. "That man's taken him! I know it! I know it!"

"Because of that man." She pointed to her husband. "He thinks more of his money than he does of his son and me."

"Of you, my dear!" Hofton Wales turned furiously on his wife. "Do you think I'd pay £10,000 for you? Get that out of your head, quick!"

Frost interposed hastily, asking for the telephone. Wales took him and Hoy into a room he named his study. He locked the door and withdrew the key.

A look of disgust came on Frost's face. He tinned, without a word to the' telephone and called St. Anthony's College.

Herbert Wales, junior, had been at the college that day. He had left for home at the usual time, three o'clock. One of the masters had spoken to him as he passed through the college gates.

Frost asked who had accompanied the boy from the College? There was a long wait, and then a strange voice answered, naming two youths.

The Inspector repeated the names to the financier. Wales knew both families. The nearest lived about a quarter of a mile from the Wales house.

Frost rang up the house, yes, their son, Colin, had come home. There was delay while the boy was found. Herbert Wales had parted from him at his gate, intending to go straight home.

Then the abduction, if there was an abduction, had taken place between the two houses, somewhere over the quarter of a mile of road. Frost seized his hat, and, accompanied by Roy and the financier, walked over the ground. He could see no signs of a struggle. A keen search while on his way back, revealed no clues to the missing lad.

"Dr. Night doesn't make mistakes of that kind," he said in a low voice to Roy. "Now, all we can do is to wait until the scoundrel formulates his demands. They'll hurt Wales, I know. But, I don't think the doctor will harm the boy. No, Wales's money-bags will be the only thing to bleed."

Again at the house they had to face another interview with the distracted mother. On the pretext of a conference Frost retreated to the study, with Roy and Wales.

"What's the next move?" asked the financier, impatiently. "Are you going to sit here all day long, doing nothing?"

"Get out and arrest this Dr. Night. That's your job!" Wales spoke brutally. "That's what we pay you for."

"As it happens you do not pay me," Frost was stung to retort. "I am paid by the people of New South Wales, where men of your kidney are in a hopeless minority, though you make the most noise."

The telephone bell Jangled. Wales turned from the window, but Frost reached out a long arm and took the instrument.

"Ah, my friend Hofton Wales," the suave voice mocked. "Certain instructions were sent to you, today. You did not obey them."

"You lie." There was no heat in the voice on the lines. "Yesterday you paid into your bank eight thousand pounds, the proceeds of the sale of certain lands. The payment was made by certificated cheque. At that time you had in credit nearly six thousand pounds. Again I say, you lie."

"Instead of withdrawing that money from the bank you went to the police." The man laughed slightly. "I had you watched and know. Consequently, I acted. Herbert Wales, your son is in my hands."

"Ah!" Again laughter, cold and sinister, came over the wire. "So it is my good friend, Inspector Frost who speaks for Hofton Wales. Still—what does it matter? Will you tell me. Inspector Frost, which does Hofton Wales love best—his son or his money bags?"

"His son will cost him £20,000. When I know that he is anxious—not willing—to pay, I will talk with him again."

Very deliberately Frost replaced the receiver on the instrument and turned to the financier.

"Dr. Night demands a £20,000 ransom for your son. He adds that when he is convinced that you are anxious to contribute that amount to his fund he will deal with you."

The telephone bell rang again. Frost waited at the door while Wales answered the call.

"That Frost? Thomas, of the Mirror, here. Police Headquarters told me you had gone out to Wales's place. There's been a further development in the Dr. Night matter."

"Albert Wilson has been called upon for a contribution of £25,000. He is here, in my office. I'll hold him until you come."

CHAPTER XV

"HOLD him!" Frost spoke briefly. He turned to the financier. "Dr. Night moves quickly."

"Not you." The detective showed his disgust. "He's struck at a friend of yours-Albert Wilson."

"That your advice to him?" The Inspector laughed. "Wants something like £25,000. Says that includes the £10,000 you forgot to draw from the bank this morning."

"He will release my boy if Wilson pays that?" Wales exclaimed. "Of course, he must."

"Not too sure of that." Frost spoke grimly. "You men of money are not too fond of paying one another's debts. If I guess right Wilson will follow your lead."

"He'll refuse to pay; then set up a mighty wail when Dr. Night carries out his threat."

"But—" The financier hesitated. "What are you going to do? Are the police entirely inefficient? What do we pay taxes for? If there was one man of sense in the whole Police Department Dr. Night would be behind bars by now."

"Of course." The detective laughed shortly. "Men of your kidney seem to think that we have all the criminals in the world docketed and in pigeon-holes, When one of you is threatened all we have to do is to fill in the docket card and send him to Long Bay. Come on, Roy. We're wasting time here."

"We are." The Inspector turned to the driver. "Mirror offices, and make it nippy."

Frost leaned across Roy. "I'm speaking as a father, not as a police officer," he said, slowly. "If Dr. Night took my son and demanded ransom, there's one thing I'd do before I stirred up the police."

"I'd get my son back, if it cost me the last penny I had or could beg, borrow, or steal." He sat up and spoke to the driver. "Now, Johnnie, taken root here?"

The car moved forward with a jerk. For some time Frost sat with folded arms, frowning thoughtfully. Roy watched him, curiously. The Inspector had always, in his recollection, shown himself good-tempered and patient with people in trouble Yet he had not appeared to make the slightest allowance for the financier's sufferings under the loss of his son.

The journey back to the city was quickly accomplished. As the car drew up at the doors of the Mirror's offices the Inspector sprang out and raced up the steps, closely followed by Roy. He pushed the Inquiry Clerk on one side and strode into Alphonse's room. As he entered his eyes sought a man seated beside the big desk.

"Inspector Frost." Thomas explained to his caller. "I think you had better tell your story again."

"Oh!" The man looked up at the detective and gave a sigh of relief. "Mr. Thomas told me you were coming here. I waited."

"So I see." Frost spoke grimly. "Now, tell me why you came here and did not go to Police Headquarters?"

"I read the letter from Dr. Night in the Mirror." Wilson spoke hesitatingly. "I thought—"

Thomas lifted an envelope from the desk and passed it to the Inspector. The envelope was of medium quality and contained only a single sheet of notepaper.

Its context was similar to the one Hofton Wales had received, the only variation being in the amount demanded.

"Green Messenger boy brought that to you?" The detective demanded. "Sign for it?"

"You know the receipt books they use. Was that in order? Not a new one? Who was the previous recipient of a letter, or parcel recorded in the book?"

"I didn't notice that." Wilson spoke hesitatingly. "The book and the boy appeared to be regular, and in order. I signed for the letter opposite my name, and tipped the boy."

"Thanks." There was a note of sarcasm in the Inspector's voice. "Open the letter while the boy was with you?"

"No. I didn't think it important. I left it lying on the desk while I finished some work—about a quarter of an hour."

Frost nodded. He glanced at Roy and nodded towards the telephone. Roy went to the instrument and glanced at the Inspector, to And him frowning. He replaced the telephone on the table and went out of the room, going to the switch room. Ten minutes later he re-entered the editor's room and nodded, significantly, at the Inspector.

"That, as usual, a pile of time has been wasted." The detective frowned. "Why, in the name of little apples, you didn't go to Police Headquarters, I can't understand." He spoke to Wilson. "I'd made arrangements to cover a situation like this. Now—" He made an expressive gesture.

For some minutes he strode up and down the room, the three men watching him curiously.

"There's new matter in this," he said at length. "First the time limit is very short." Again he turned to Wilson. "What reason has Dr. Night to suppose you can lay your hands on £25,000, at a moment's notice? He gave Wales the whole of the day."

"I have bonds." Wilson hesitated. "I am negotiating a big loan and found it might be necessary to make a preliminary payment at any moment, probably outside banking hours. I obtained certain 'bearer bonds' and kept them in reserve."

"So!" Frost meditated. "Well, you got this letter. What were your impressions on reading it?"

"I would have thought it a joke but for the article in the Mirror. I came here to ask Mr. Thomas if he had any information that he had not published."

"Which of your possessions do you value chiefly—of course, excluding your banking account?"

"I have many treasures." Wilson drew up his spare tall figure. "I have a reputation as an art connoisseur."

"So is Dr. Night." The detective paused, then changed his line of examination. "Let's go back to your receipt of this letter. You had read the article in the 'Mirror' and knew you were not up against a joke. Had you thought of complying with Dr. Night's demands?"

"Complying with the demands of a blackmailer?" The thin, hawk-like features of the man sharpened. "Of course not."

"You know now that unless his demands are complied with Dr. Night acts immediately? Hofton Wales lost his son within an hour of the time-limit given him."

Frost took his watch from his pocket and watched the dial for a few seconds. "Name one of the things you value most."

"My Murillo." Wilson answered without a thought. "Then I have a unique collection of cameos I bought last February at the—"

"You know the time-limit Dr. Night gave you has expired?" Frost's voice had become normal again. "Like Wales, you will get no second chance."

"What can he do?" Wilson laughed loudly. "I have no family. As for my art treasures, they are well guarded. The house is impregnable; by night and by day two ex-soldiers, armed, are on guard."

"And I'll back Dr. Night." Roy half whispered. Frost overheard them, and smiled whimsically.

"All in order. A young lady went into the Green Messenger offices in Her Majesty's Arcade and handed in a letter to be expressed to Mr. Wilson. The boy who delivered the letter is named Fred Parsons. He obtained a proper receipt for the letter. He is out at the moment but directly he returns he will be sent to you."

"Thought so," Frost nodded. "Dr. Night doesn't make those sort of mistakes. A young lady, eh?" For some moments he mused. "There was a young lady with Dr. Night in the Green Pearl case."

"Only that Dr. Night has scored again. He has infernal luck." Frost flung himself into a chair. "Say, Mr. Wilson, what do you value that painting at?"

"Value it at?" The financier showed surprise. "Man, do you know that it has no appreciative value. If I sold, and I am not likely to do that, I would send it to London, to Christie's. What it would bring under the hammer depends entirely on who were in the market for Old Masters."

"Still, it has a value." Frost spoke impatiently. "Oh, damn it, man, can't you think? You've wasted time, all round. You've wandered up here to get information from Mr. Thomas Say, what time did you come here?"

"Dr. Night made his demand on you at three-thirty." Frost ticked off his points. "You were told to get the money and leave Sydney for Moss Vale exactly at five o'clock. I believe that is your usual time to leave your office when you go to Moss Vale?"

"Dr. Night informed you that you would be met, en route, and relieved of your burden—the money. What, in the name of Mike, were you doing between three-thirty and six?"

"I took time to consider the position." Wilson spoke with dignity. "I considered I should obtain much more information before I acted. In pursuit of that information I came to Mr. Thomas."

"While Dr. Night went to Moss Vale." Frost laughed. "Mr. Wilson, I'm afraid the Asian has again collected tribute."

"I can't say exactly, but I'll hazard a guess that you have already paid the price. It may be the cameos—"

"Then—you saved £25,000 of bearer bonds this afternoon, and will pay £50,000 to reclaim your treasure—some day. I'm beginning to understand how Dr. Night intends to make up that half-million! He's clever!"

CHAPTER XVI

"Come and see." Frost moved to the door. There he paused. "Come with us, Roy," he said, briefly. "There's news here, unless I'm much mistaken."

In silence they went down to the police car, Frost motioned Roy to the back seat, beside Wilson, and took his place beside the driver.

The long journey through the evening dusk was not pleasant for the newspaperman. Wilson was a moody companion, continually complaining—and Roy had much to ponder over.

Dr. Night had acted with his usual speed. They had been prepared for the demand on Hofton Wales; but the attack on Albert Wilson had been so sudden that there had not been time to prepare a defence.

Why had Dr. Night made the demand on Wilson immediately after he had abducted Hofton Wales' son? Every sign showed that the master criminal had teen prepared for the second move. Roy decided that there was only one answer to the question. The Asian had not anticipated that his demand on Hofton Wales would be acceded to. Wales' hesitation and refusal to pay had played its part in the very complex scheme to rake from the twenty business men of half a million sterling.

Dr. Night had demanded £10,000 from Wales and £25,000 from Wilson. But the second demand, the £25,000, had been definitely stated to contain the £10,000 demanded in the first instance. If the Asian had stuck to his original demands he would not have raised half of the sum he demanded. But he was working an accumulator of vast proportions on the men. Each successive demand would contain all previous demands unpaid. In addition the crook would have obtained from each man who refused his demand something of great value. That "something" would have to be ransomed—at the Asian's valuation.

Roy tried to work out the sum, mentally, and staggered in review of the figures he produced. Under-the accumulator Dr. Night would demand over a million pounds from each of the last two men of the twenty. And, he had declared that all he wanted was half a million!

What then was his objective? Did there lie behind the demand for a half million pounds some design deeper and far more sinister?

Roy puzzled the problem. He could only arrive at one conclusion. Dr. Night had compiled a list of twenty financiers in the city. But that list was only a blind. He would hit at but a few, and those the men who were most selfish and greedy.

The car rolled down the long hill above Moss Vale and turned into a narrow lane to the left. A few hundred yards further and it swung into a private road and pulled up before a huge two-storeyed building of rather ornate design.

Albert Wilson was out of the car almost before it stopped and ran up the steps to the big entrance doors. Almost before Roy and Frost were out of the car he was pressing the button of the electric bell.

No one answered. Frost mounted the steps slowly and stood behind the art collector, a strange, quizzical smile on his lips.

Roy had not mounted to the hall door. He wandered around the side of the house, curiously scanning the windows. He turned the second corner and hesitated.

What was wrong with the house? For some time he puzzled to find a reason. Then, in an illuminating flash, he understood.

The house was silent, deserted. There was not a soul in sight; yet Wilson had stated that he kept a large staff permanently at the house.

Close by where Roy had halted a door stood open. He went to it and looked in He found himself staring into a big kitchen. Seated at a big table in the centre of the room was a large woman, wearing a coarse apron. She lay back in her chair, fast asleep.

ROY stepped into the kitchen and stared about him, curiously. A door opened to the left. He peered into the room, to see two men lying on the ground, apparently insensible. He went in to them. They were fast asleep.

From another door a short flight of stairs ran up to the big hall. Roy mounted them, two at a time. In the hall, which extended up to the roof of the house, he glanced hastily around, then went to the hall door and opened it.

Wilson, his face ghastly pale, charged into the great hall. In the centre of the hall he stopped suddenly, a grey-green pallor coming over his face. With a little, choking cry he toppled forward, insensible.

Instinctively Frost and Roy glanced towards the spot at which the financier had stared. On the wall hung a heavy ornate, dulled gold frame. But it contained no picture. In the centre of the bare space was a single sheet of paper Roy went and stared up at it. There were only three lines of writing and a signature:

Received from Albert Wilson one picture, reputed to be by Murillo, of the estimated value of £50,000.

—Dr. Night.

Two hours later Frost and Roy left Moss Vale in the police car. In the house they left Wilson, under the care of a physician, delirious and babbling of lost pictures.

"Think so?" The detective laughed. "All the devilment I see in our friend, Dr. Night, lies in the speed with which he acts. He gives his victims no time for consideration and that means that we, the police, trail along helpless, in the rear. Still—"

The detective spoke serenely. "That will be our opportunity to catch up, and we will."

"That's true." The Inspector was silent a moment. "He's got Hofton Wales' son to ransom, and Wilson's pet painting. For the latter he asks £50,000. He hasn't put a price on the former, yet—"

Roy did not answer. Frost had arrived at the same conclusion to which he had been working. Dr. Night made a demand on his victims, but that demand was but a blind. He knew that these men would not accede to his first demand. Then ne took from them something they valued highly. For the return of his capture he asked much.

Frost dropped Roy at the doors of the Mirror offices and drove on to Police Headquarters. The newspaper-man went up to the big reporters' room, to find, on his desk, orders to report to the managing editor immediately he returned. He went across to the editorial room, knocked and entered.

"The receipt stated that the picture was worth £50,000." The newspaper-man, spoke significantly.

"Fifty thousand pounds!" Thomas whistled, lowly. "He's not modest in his demands. How did Wilson take it?"

"Badly. Went down in a sort of fit. We left him in bed with doctors and nurses in the offing."

The managing editor leaned back in me chair and surveyed the reporter, quizzically. "You don't seem to have much sympathy with your fellow men, when they are in trouble, young fellow?"

"With that crowd?" Roy showed disgust. "All they think about is money—and getting it."

"A common complaint in the good city of Sydney." Thomas laughed. "Write it up, Roy. You've got a good story for the day. Wales and Wilson! Jove, Dr Night makes news."

"Not a thing. I telephoned there hall an hour ago. Halliday is waiting to hear from Dr. Night. I'm betting he'll pay at the first call. He's completely broken up."

"Went out to the Halliday's place." Thomas shuffled some papers, then looked up. "By the way, Roy, you're running this end of the story on your own. Don't fall down on it."

"Sir Max has commandeered him for a few weeks. Halliday is handing over plans of the aeroplane, and Hardy is to supervise construction. By the way, he says you are stopping with him at Pott's Point. Asked that you should get home as soon as possible. Think he has some news for you. Get to it, young fellow. Get that story to the sub's table—and get off."

Roy went to his desk. For some time he sat smoking. The story would not frame itself. From which angle should it be tackled? Into his thought continually intruded Ruth Halliday.

Ruth was in the hands of the arch-fiend, a prisoner. But a prisoner for whom no demand for ransom had been made. The coincidence came to Roy. Young Wales had disappeared, and Dr. Night had not declared his Intentions. Only in the case of the picture had anything like a demand been made for a definite sum—and that indirectly.

Suddenly the story took shape in his brain. He dropped his feet from his desk and swung open the typewriter.

Without pause, almost without thought, sheet after sheet of copy came from the machine. The story was good, one of the best things he had written. With unconscious art he worked carefully to his climax; then:

"Roy Iston!" He looked up to see Thomas standing beside him, the sheets of copy in his hand. "Good man! One of the best stories the 'Mirror' has ever had. But you'll have to alter this ending."

"Because of this." Thomas dropped a typed letter before the journalist. "Dr. Night's potential victims have decided to hold a meeting for mutual protection."

"Can't see them doing that—but there's copy in it." Thomas joined in Roy's laughter. "The 'eye of the needle' story is more probable than those twenty men contributing half a million for nothing."

The telephone on Roy's desk rang impatiently. He lifted the receiver and spoke his name. Thomas was moving towards his room when Roy stayed him, covering the mouthpiece of the instrument with his hand.

"Dr. Night has spoken, sir," he said in an undertone. "Halliday received a message from him to-day. Ruth will be returned in exchange for the secret of the gravity plates."

CHAPTER XVII

TWO days later the meeting of the twenty financiers threatened by Dr. Night took place.

Alphonse Thomas received an invitation to the meeting. Britton Chambers, who had called the meeting, telephoned him a special invitation. The meeting was to be held at the Hotel Zenith and the managing director arranged that Hardy and Roy should accompany him.

Roy looked around the room, curiously, as he entered. The twenty financiers were seated at a large oblong table, each with writing utensils before him. Close to Britton Chambers, who was seated at the head of the table, were Hofton Wales and Albert Wilson, the latter looking pale and worn.

In a corner of the room, remote from the meeting, Roy noticed, with surprise, Inspector Frost. When the necessary introductions had been made, Roy crossed to the Inspector's side and drew up a chair. Thomas and Hardy were accommodated with seats near, but not at, the table, slightly behind the chairman.

For some minutes after they entered there was an awkward pause. Chambers glanced at the men seated around the table and blew his nose, loudly. Roy took stock of him. A short, thick-set man of about fifty years of age, with a full, florid face. His hair was very thin but carefully arranged to cover the glowing bald patches on his head.

Chambers coughed loudly, tugged lustily at the massive watch-chain stretched across his large, rotund waist, then levered himself to his feet.

"Gentlemen." He cleared his throat again. "Rather unusual, this meeting. Never known one like it before. But we've had proof it's necessary—yes, necessary."

"Pish!" A tall, thin man at the opposite end of the table sneered, openly. "What's all the talk about? Someone's tried to blackmail one or two business men and the newspapers have played it up for all it's worth."

"I'm speaking, Mr. Sullivan." Chambers spoke impressively. "I've convened this meeting and propose to open it in due form. As for your insinuations," he looked around him, triumphantly, "I've taken means to nail them—nail them, sir. I have here the very respected editor of the newspaper in question. I have here—" he tapped a paper on the table before him, "—the identical letter this blackmailer, Dr. Night, sent to the newspaper. Now, what have you to say to that?"

No one answered, Chambers glanced around the room, triumphantly, then continued:—

"More than that. Here's Mr. Hofton Wales, well known to you all. He's lost his boy. Here's Mr. Albert Wilson. Two days ago he lost his Murillo—"

"What's that?" A stout young man on the right of the table glanced up quickly "Maybe a racehorse, but it sounds like a cigar."

"A valuable painting, sir." Chambers waved his hand, largely. "A painting valued at £50,000. Dr. Night demands that sum for its return."

"We are all in danger. You know how this blackmailer works. He acts quickly." Chambers was working himself into a state of excitement. "Dr. Night has attempted to blackmail Hofton Wales and Wilson. They resisted his demands and have been—been—"

"Yes, robbed." The chairman bowed. "They resisted this criminal's extortions and were robbed. Who will he attack next?"

The men looked at each other, anxiously. Chambers had brought the problem home to each of them. They had come to the meeting out of curiosity; perhaps to see the two men who were the victims of the blackmailer.

But, to consider themselves open to the same attack: to have a sudden, irresistible demand made on their banking accounts, was a different matter. They glanced at each other: around the room, with growing uneasiness. Who was to be the next victim?

"That is what we have met here to consider." Chambers spoke with dignity. "Have you a proposal to put before the meeting, Mr. Lefty?"

"Yes, you." The chairman beamed on the man. "Just you, Mr. Lefty. Dr. Night demanded £10,000 from Mr. Hofton Wales. When he did not get it he demanded £25,000 from Mr. Wilson. I believe I am right in saying that in that sum Mr. Wales' unpaid £10,000 was included. His next demand will be for between forty and fifty thousand pounds."

"A proposition in mathematics, Mr. Lefty. He, Dr. Night, is running what may be termed an accumulator."

"And who's elected to pay that?" Sullivan jumped to his feet. "Look here. Britton Chambers, there's something damned funny in all this. How do you know that Dr. Night will demand £40,000? Perhaps you can tell us who is to be touched next—"

Who had spoken? The men around the table glanced from one to the other in amazement. Who had spoken the name?

Who? The chairman had sunk back in his chair. Now he leaned forward, his hands open and pressed on the table. He glanced from one man to the other, receiving from each a negative shake of the head.

Roy looked at Frost. The detective had abandoned his air of nonchalant unconcern and was leaning forward, his eyes searching the room. Roy gazed around him, in amazement. The voice had not been loud, but penetrating. It had rung clearly, yet softly, through the room.

"Someone spoke my name." Britton Chambers struggled to his feet. "I distinctly heard him. I demand to know who spoke. Someone said that Britton Chambers was to pay the £40,000."

"A slight error, Mr. Chambers." All eyes turned towards the door, from near Where the voice came. "The amount should have been £50,000."

Roy could have sworn that the door had not opened, yet before it stood a slight, wiry man. Grey was the colour that best described him. He was dressed in grey, even the skull-cap fitting closely to his head was grey. From under it straggled grey locks, blending with the grey eyebrows and grey-tinted skin. From under the heavy eyebrows looked out two brilliant grey eyes, piercing in their intensity.

"Dr. Night!" Although Roy had never seen the Asian before he recognised him at a glance.

The words were barely breathed, yet the Asian's eyes turned towards Roy. The newspaper-man had the feeling of a sudden cold douche.

"Dr. Night, at your service, gentlemen." The Asian spoke slowly, in cold, suave accents, with a slight foreign intonation.

"Mr. Britton Chambers mentioned an incorrect sum. I crave pardon for correcting him."

"You are Dr. Night?" Hofton Wales leaned forward across the table, staring at the man, hungrily. "You stole my son."

"He is well." The suave voice never faltered. "At the moment he is in charge of two young ladies, the Misses Halliday and—I assure you they will take great care of him."

"I asked ten thousand pounds as a contribution to a fund for an Australian genius I have discovered. You refused."

With remarkable speed the financier pulled a gun out of his hip-pocket and levelled it at the Asian. Roy sprang to his feet with a shout of warning. Dr. Night did not heed him. His keen grey eyes were fixed on Hofton Wales.

The automatic came up, levelled at the slight figure of the blackmailer, yet the financier did not pull the trigger. For a moment the weapon remained motionless; then slowly the wrist and arm bent, as if under great compulsion.

A look of agonised alarm came on Hofton Wales' face. His arm was curving round. The muscles of his face and body tensed under the strain; yet the arm continued to curve.

The automatic now pointed towards the head of the table. Britton Chambers slipped from his chair to the ground, only his eyes and forehead showing above the table level. And still the arm continued to curve.

Frost was leaning forward, every muscle of his body tensed. His eyes were fixed on the Asian, with a look of intense hatred—yet in his eyes was almost an appeal.

Roy tried to move from where he stood, but his body refused to obey his will. All he could do was to watch—watch the curving arm carrying the deadly weapon towards Hofton Wales' temple.

He glanced from man to man seated around the table. Not one of them had moved. Lefty was holding the arms of his chair, as if preparing to -spring to his feet; but his muscles were relaxed. And still the gun swung round in the deadly arc. The muzzle was now pointing to Hofton Wales' forehead. The arm shortened until the cold steel touched the flesh.

"If it were my will." Dr. Night spoke slowly. "But the taking of life is an offence to the gods. Drop that gun."

The weapon fell with a clatter on to the table and lay there unheeded. Dr. Night glanced around the group of men.

"If I willed." The words dropped as chilled water on the hearers' ears. "I could kill each of you as you sit. If I willed, you would give to me that which I demanded. But, you would give it of my will, not of your will. That which I take must be freely given."

For a moment he paused. Now he glanced at Hofton Wales and his eyes appeared to pierce into the man's brain.

"For your son, a ransom. The amount you named. Twenty thousand pounds. You shall bring it to me when and how I will."

Dr. Night bent his head. The door behind him opened to invisible hands. He raised his right hand over his head in a queer beckoning motion; then stepped back and the door closed on him.

CHAPTER XVIII

FOR the space of ten seconds there was neither sound nor movement in the room after the door closed on Dr. Night. Roy looked at the men at the table. They sat as if frozen into immobility. Hofton Wales stood before his chair, his eyes cast down on the automatic lying before him on the table. Behind Britton Chambers sat Alphonse Thomas and Hardy, the latter with a thin smile growing on his lips.

Roy swung round on his chair to view Inspector Frost. The detective was leaning forward as if about to spring to his feet, his hands resting on his knees: his muscles tensed. Almost as the reporter turned the Inspector sprang to his feet and charged across the room to the door —to halt there in wondering amazement. Roy followed him more slowly.

"You thought Dr. Night was at the door." The detective turned at the sound of Hardy's Voice behind him. "He was there. Now he's gone.

"Gone." A look of blank amazement was on the detective's face. "Why, he's only just entered. I saw the door open and him enter. It has not opened since, I'll swear."

"Wake up, map." Roy caught the detective by the shoulders arid shook him roughly. "The show's over."

Roy pointed to the door. The Inspector dashed forward and pulled it open. Large clouds of light-blue smoke rolled into the room.

Hardy was the first to sense the danger. He dashed across the room to the windows, flinging them open. Roy and Frost backed against the wall beside the door, holding their handkerchiefs to their mouths and nostrils.

The smoke rolled into the room as ii propelled from a gun. It enveloped the men seated at the table, then spread until it filled the room. Some impulse caused Roy to hold his breath. He saw Frost slip to the ground beside him and then the light-blue gas blotted out all view.

As suddenly as it had come the gas disappeared, leaving the room a litter of sleeping men. Roy staggered to one of the windows and thrust his head out in the open. A few big gulps of fresh air and he looked back into the room. Almost at his feet lay Robert Hardy.

With an accession of strength Roy lifted the chief sub. and thrust his head through the window A few minutes and Hardy returned to consciousness.

"Dr. Night wins again." The words came slowly, in a low whisper, accompanied by a little laugh.

"Mo better for my second dose of Dr. Night's gas."' Hardy leaned far out of the window, gulping in the pure fresh air. He looked back over his shoulder into the room. "He got them good and strong, that time."

"Where are you going, Roy?" The chief sub. held out a staying hand. "No good trying to follow Dr. Night. He had his getaway well arranged."

"Let them be. They'll be conscious in a quarter of an hour, if they do feel heavy and sick, afterwards. Lor', man, don't you recognise that we've got the Story of the day? This is a Mirror scoop. Not another newspaper man within sight."

Roy hesitated. He watched Hardy drawing great gulps of fresh air into his lungs, then walk across to the big table. There he joined him, going from man to man, making a careful examination of Dr. Night's victim's.

Between them they took Thomas and Frost to the Windows, reviving them. Once Frost understood what had happened, he sat by the Window, his brow drawn and black.

"That's the end of me," he muttered. "To sit here like a stuffed pig and watch Dr. Night loot the crowd. The Commissioner won't stand for that."

"Then the Mirror will have a Word with the Commissioner." Hardy clapped the police officer on the back. "You're not expected, to do the impossible, Frost."

"Dr. Night is—and you know it." Hardy paused. He turned to his chief. "How are you now, Mr. Thomas? Able to walk?"

"In a damned bad temper," Alphonse Thomas laughed. "I never thought one man could hold up a roomful of people, put them to ransom, and get away by walking out of the door. What was it, Hardy?"

"Mass mesmerism." The chief sub. smiled, reminiscently. "Inspector Frost is a good example of what happened in our minds. He saw Dr. Night enter and from that moment time stood still for him. He saw Hofton Wales forced towards suicide, but it was as a side-issue to Dr. Night's presence. So far as the Asian is concerned, to Frost, he walked in at the door—and disappeared."

"Let's get out of this!" Roy exclaimed, suddenly. "The place makes me sick. Come on Frost." He took the man by the arm and pulled him to his feet. "Bob, you bring Mr. Thomas."

They left the room, a roomful of unconscious men, sprawling around a large table—and closed the door. Without speaking to anyone in the hotel they went out on to the street and walked up to Phillip Street.

"You're publishing this?" Frost spoke, halting before Police Headquarters' main entrance.

"Of course." Thomas answered. "Don't worry, Frost. The Mirror's behind you. We'll see you right, and besides—" he hesitated "I've got a hunch you'll lay a heavy hand on Dr. Night's shoulder yet."

"And have him making me do tricks like a performing pig." The Inspector grunted. "We like to slip the 'cuffs on a dangerous criminal as quickly as possible, but with Dr. Night—damn it, we'd have to blindfold him first."

At the door of the Mirror building Roy hesitated. Hardy looked at him inquiringly.

"Mr. Hardy will write that, Mr Thomas. Not waiting for a reply, Roy sped down the street.

"Not write the story!" Thomas gasped in blank astonishment. "Give Up a good story to—" Then he caught Hardy's eyes.

"Got something good on, eh? Know anything about it, Hardy? No, well, Well! You do the story and we'll see what the cat brings in."

A sudden thought had struck the reporter. He had been conning Frost's and Hardy's stories of what had happened at the conference, as he had walked up the street, one thing had struck him. While the others had seen all the incidents as he had, they had, to them, been distorted and lacking in rhythm.

He had seen the events of the brief minutes after Dr. Night had entered the room in logical sequence. Perhaps he had not come too strongly under the Asian's mysterious influence—or perhaps the gas had fogged their intellects. He had hardly smelt the gas; all he had experienced had been but a slight, momentarily dizziness.

He remembered the words Dr. Night had spoken to Hofton Wales and Albert Wilson. He had named to them the ransom that he required for the child and the picture. And they were to bring the price to him at the time and place to be conveyed to them later.

Did, in those words, lie the secret that would bring the Asian's downfall? Roy wondered. It had been an impulse that he had left his companions to return to the hotel. He wanted to see and study the two men when they had returned to consciousness.

At the Hotel Zenith he went into the lounge and found a chair so placed that it commanded not only the grand staircase, but the elevator doors. If he knew his men, they would come down to the lounge. Then he could observe them; try and discover what effect Dr. Night's words had had on them.

He had a long time to wait, but he knew that no one would enter the conference room without permission. Britton Chambers had given orders to that effect.

At length the elevator doors opened, and a group of men emerged. Roy recognised them as members of the threatened twenty. But neither Hofton Wales nor Wilson was of the party.

The men dispersed, and again Roy settled himself to wait. A quarter of an hour and the two men he awaited came down the stairs together, talking eagerly.

For some time they stood in the lounge debating some question. Roy sauntered through the crowd until he stood almost beside them. He strained his ears. If he could gain some clue as to which man to watch.

"We're both in the soup, though I'm wetter than you," Wilson raised his voice heatedly. "He only asks a measly twenty thousand from you. Fifty from me." Sudden exasperation shook the man. "Damned if I'll pay."

"You're mad." Wilson looked down his long-beaked nose. "Didn't you hear me telling them Dr. Night could go to hell before I'd part with a penny."

"They applauded what you said," Hofton Wales sneered. "Do you think that two of that crowd would come to an agreement—and hold it—if they found a better way out?"

"Perhaps he thought that if Dr. Night got £50,000 from you he wouldn't want to wring money from him."

Wilson frowned, uneasily. He knew that not one of the twenty men at the meeting but hoped that he might, by some fluke, escape the Asian's extortions.

"I don't know. I'm waiting to hear from the man. Anyway, I'm going to get the money now, and I'll carry it about with me until I can pay it over for my boy."

Chance had served him well. The hunch that he had developed outside the Mirror's' offices had worked. Wales had decided to pay.

Dr. Night would approach the man for the money. Roy was certain that the Asian was having his Victims patched. He would know immediately Wales took the money from the bank. He would then get in touch with him, telling him how the money was to be paid over.

And, perhaps in his eagerness to obtain the money, he would make some slip. One false move would give the clue to the Asian's hiding place. Perhaps there was hidden Ruth, the boy, and the picture, perhaps in that secret plaice was stored Halliday's mystery aeroplane.

Roy watched the man stride down the street. He sauntered along some distance behind him, just keeping him within sight. He saw Wales turn in to the bank and composed himself for a somewhat lengthy wait, standing at the street corner so as to command both exits.

"You're Roy Iston." A heavy hand brought the newspaper man out of his reverie. "You were at that meeting today. Where did you get to?"

"You saw everything?" Chambers' tones were earnest. "You saw that man come into the room?"

At Roy's nod Chambers caught him by the arm. "Come up to my office. I've got something to show you."

Roy hesitated, then consented. He would lose sight of Hofton Wales for the time, but he could pick up the trail later. It would take time for the news that Wales had withdrawn the money from the bank to reach the Asian. Then he would have to formulate his plans to safely acquire it.

Britton Chambers led Roy to Bramston House, in Pitt Street. On the first floor he opened a door with a key attached to his watch-chain and motioned Roy to enter. He locked the door after them carefully.

"Smoke?" He shoved a box of cigars across the desk. Then, abruptly, "You say you saw everything?"

"You saw Dr. Night hypnotise the lot of us? Well, what were you and Frost doing that you did not interfere?"

"Frost was hypnotised. I hadn't strength left in me to move." Roy laughed with some embarrassment.

"Thought so." Chambers paused. "You saw that fiend nearly force Hofton Wales to suicide? Yes. You heard him tell him that he would restore his son for twenty thousand? Yes. You heard him tell Wilson that he could have the picture back for fifty thousand? Anything else?"

"I heard him tell you that he had you down in his books for fifty thousand, not forty thousand," Roy smiled. "But he didn't give you a date to pay on."

With a quick movement the financier opened a drawer and flung an envelope on the table before Roy.

CHAPTER XIX

ROY stared at the envelope. He could have sworn that not an incident had escaped his eyes from the moment Dr. Night had entered the room until Frost pulled open the door to face the light-blue gas.

Yet this man, Britton Chambers, definitely stated that Dr. Night had placed this envelope on the table before him. But at no time had the Asian moved from before the door!

"You say that Dr. Night placed the envelope on the table before you?" the journalist queried.

"He must have." Britton Chambers rubbed his partially bald head in perplexity. "I didn't see him do it—but I found it there, and—" he paused—"it's from him."

Roy withdrew the enclosure and read the few lines. As he had anticipated, it was a demand for fifty thousand pounds. This time the recipient was to withdraw the money from his bank exactly at noon the following day and carry it in a brief bag. Somewhere and sometime, before nightfall, the bag would be taken from him.

"Nice sort of game!" Britton Chambers had lost all the pomposity that had distinguished him at the meeting that afternoon. "Walking around town with fifty thousand dangling from my fingers, waiting for someone to lift the bag. Why any old dead-beat could hold me down. And this damned doctor doesn't propose to give me even a receipt!"

Roy laughed. The spectacle of Dr. Night gravely handing over a receipt for a blackmailing payment appealed to him.

"Oh, laugh away!" Britten Chambers growled. "Thank your stars you're not a moneyed man."

"Depends on what you've got." Roy was thoughtful. "Dr. Night likes payment to his order. He's apt to get crotchety and take about twice as much as what he demanded in the first instance. Got anything valued at about a hundred thousand pounds?"

"Look here, young man," he exclaimed at length. "Put yourself in my place. Say you've got something like a quarter of a million. Would you let yourself be blackmailed for a fifth of it?"

"Humph!" Britton Chambers paused and stared at the newspaper man. "That's an idea! But you couldn't play that game as a lone hand."

"Dr. Night might let Hofton Wales carry the money around for a few days before claiming it. You'd have to be on the watch every minute of the time. It's all odds to nothing that the moment you started to nod Dr. Night would step forward and annex the swag."

"I might." A cunning smile came on the man's face. "Look here, young man, you're a reporter on the Mirror aren't you? Your editor'll answer for you? Guarantee you're honest?"

"And you thought to do so by playing tabs on Hofton Wales? Now, what about playing the game with me?"

Roy thought quickly. What was this man's game? He did not believe Britton Chambers would willingly hand over a fortune to Dr. Night; yet that was what he proposed. The man would bear watching.

"I propose to go to my bank to-morrow at noon and withdraw fifty thousand pounds in notes of small denominations—Just as that scoundrel instructs me. I'll place them in a handbag and toddle off—"

"Well?" Roy asked as the man paused. "Well, you'll me. You'll have a similar bag to mine. I'll get a pair that Dr. Night won't be able to tell apart. You'll stand beside me at the pay teller's desk. When I pick up your bag you'll pick up mine and follow me, about twenty yards behind, to this office. If I go out again I'll carry my bag, but you'll leave yours here. You'll follow me until you see someone take my bag from me, then you'll follow him."

"I want you in the bank and as a guard until the right person takes the bag from me." Britton Chambers spoke quickly. "If you went into the bank without something to show business then you'd draw the attention of Dr. Night's spies to you and the game would be up. See? Now. there's' one other thing. We'll want that police Inspector of yours in the game. Can you tip him off to follow you through the day?"

"Don't tell him more than is necessary," advised the financier. "Tell him that I'm taking the money from the bank and that you're tracking me, to get on Dr. Night's tail. See?"

The newspaper man nodded. He was not satisfied with the plan, but it was infinitely better than his scheme to track Hofton Wales until Dr. Night or one of his agents went to him.

With a curt farewell to Britton Chambers the reporter went down to the street. The financier had arranged that one of the duplicate bags was to be delivered to him at the Mirror offices early the next morning. He was not to come in contact with or speak to the financier. At the bank he was to manage to be next to him in line at the window; then to follow him until he reached his office.

"Looks like it. I'm beginning to think that Dr. Night will get his half million easily. Hofton Wales is paying money, in spite of his boast Albert Wilson will ransom his picture."

"Humph!" Hardy paused. "Suppose you'll be surprised if I told you that there's not a genuine Murillo in Australia, outside of the public collections."

"I don't think. I know." Hardy laughed. "No, don't ask me. I don't know what it is, yet. But—well, who knows?"

"Get to it, young fellow." Hardy laughed. He looked at his wrist-watch. "Four o'clock. Just time for afternoon tea. Then me for Ashfield."

"Oh, you don't know. Sir Max has bought up Westcox's aeroplane factory. We're getting on with the building of the gravity 'planes."

The two men had reached the tearooms. When the waitress had taken their order Hardy leaned forward to answer Roy's question.

"It's great, man. Without engines and instrument boards, it's one of the simplest machines you can conceive. Cost? About a couple of thousand each—and they'll carry a dozen people in each machine."

Hardy looked grave. "Halliday will not trust anyone with the secret. He's making the plates in that laboratory down the garden. Of course, we've got the place surrounded with detectives, but what's the good of that when our opponent's Dr. Night?"

A few minutes later the newspaper-men parted, Hardy for Ashfield, Roy for the Mirror offices, to write up the account of the day's happenings.

ROY went down to the Mirror offices next morning about half-past ten o'clock. On his desk was a small box. He opened it and drew out a brief-case of common pattern. In it were some bundles of papers cut to represent bank notes. He closed the case and loitered about the reporters' room until half-past eleven; then strolled down Pitt Street to the main entrance of the Western States Bank.

It was two minutes to the hour when he reached the bank's doors. He hesitated a moment, and as he did so someone pushed him roughly aside and strode into the bank. The main was Britton Chambers, and Roy followed to the pay teller's window.

At the desk quite a few people were waiting. Britton Chambers stood in line, with Roy immediately behind him, until his turn came. He placed his bag on the ground, at the same time making room for Roy to stand beside him.

"The cheque you telephoned about this morning, Mr. Britton Chambers?" The teller nodded. "I've the notes all ready. You have a case? Or shall I give you a bag?"

"I've a case." Britton Chambers spoke gruffly. Then, as if in sudden anger, he turned to Roy. "Who are you crowding on?"

"Stand aside, please." The teller looked up quickly. "There's plenty of time for everyone."

Roy stepped aside, bewildered and annoyed. What did the man mean? He waited until Britton Chambers lifted his bag to the counter and placed the notes in it. Then he presented the small cheque the financier had provided him with—to legalise his presence in the bank—picked up his case and walked out of the building.

For the moment he was inclined to go direct to Britton Chambers' offices, await him, and tell him where to journey. But second thoughts suggested that the man might have had some object in his rudeness. He might have been trying to indicate to any watcher that he and Roy were unacquainted.

Keeping about twenty yards behind the financier, Roy looked about for same indication of Frost's presence. He could not see the detective, so contented himself with a careful watch on the financier.

At the entrance to Bramston Buildings the financier hesitated on the steps. A man coming out of the building, brushed against him. Immediately Roy noticed that Britton Chambers was not carrying the bag. He stepped forward to get a better view of the man; but it was not Dr. Night.

A man ran across the street to intercept the stranger, now carrying the bag. Roy recognised Inspector Frost. At the same moment two men ran out of an alley-way, colliding with the detective, all three men falling.

Roy did not wait to help Frost. Swinging his bag from his fingers, he set out in pursuit of Dr. Night's emissary.

CHAPTER XX

THE man, a stocky, well-built individual, a few inches above medium height, made up Pitt Street at a smart walk. Roy followed, keeping his quarry in full sight.

His task was not difficult. The man looked neither to right nor left. At the King Street intersection he paused a few moments and Roy wondered if he was waiting for a tramcar. But when the traffic was held up he continued on.

At Market Street he turned to the right, and at the George Street intersection paused again. Crossing the road, he went up to York Street. From there he turned and twisted through city streets, lanes and arcades, until the newspaper man was on the point of exhaustion. At length he led down towards the harbour, and, turning down Martin Place, came to Pitt Street again.

There was no hesitation in the man's manner now. He knew where he was going and intended to get there as quickly as possible. Yet twice he stopped and looked at his watch.

To Roy's amazement the man turned in at the doors of Bramston Buildings Ignoring the elevators, he ran up the stairs to the second floor, Roy in hot pursuit. At a glass door he tapped, then pushed it open and entered.

Trying to appear as casual and careless as possible the newspaper man sauntered down the corridor. The man had left the door fully open. As Roy passed he turned to see the name of the person occupying the office. To his utter astonishment he read the name—"Dr. Night."

Was it a coincidence? Were there two doctors bearing the name "Night" in Sydney? Roy stopped abruptly and swung round on his heels. The open door attracted him. For a moment he paused—then, without knocking, entered the room.

It was a barely furnished office containing only a single desk, on which stood an antiquated typewriter. A large wooden cupboard, a couple of battered filing cabinets and two or three rough chairs completed the furniture.

There was no one in the office Roy looked around him curiously. A door, shut, separated the office in which he stood from the next. He went to the door and knocked. A voice bade him enter. He opened the door.

A large desk occupied the centre of the room. Behind it and facing the door by which Roy entered was a slight, grey man. The newspaper man gasped his astonishment.

"Welcome, Mr. Roy Iston." Dr. Night looked up, the brilliant grey eyes, under the heavy brows showing a mere trace of amusement. "Please come in."

Involuntarily Roy stepped forward a couple of paces until he stood almost against the desk, facing the Asian. He half-turned when he heard the door shut behind him.

"Thank you, Humberston," Dr. Night spoke gravely. "May I trouble you to relieve Mr. Iston of the suit-case he is carrying. I believe it has been a burden, to him for quite a distance this afternoon."

A man stepped to the side of the desk and took the brief-case from Roy's hand. Now he recognised the man he had been chasing for the past couple, of hours.

"Sorry to have given you so long a walk, Mr. Iston," the Asian spoke gravely. "But it was necessary that we obtained the absence of. Mr. Britton Chambers from this building before you were brought here. He waited in his office for quite a time, but you did not arrive. He telephoned the 'Mirror,' and, I believe, the police. Then he went to make a personal search. By the way, Humberston, the case you took from Mr. Britton Chambers. I believe it was the case and not your personal charm that interested Mr. Iston."

The man laid a second case on the desk beside the one Roy had carried. It was the case Britton Chambers had taken to the bank to hold the money, Roy wondered. The financier had intended Dr. Night or one of his confederates to take that case. Why had it not been taken direct to the Asian?

What had been the reason for the man, Humberston, to carry the case for so many miles around the city? The affair appeared to have no point. Why had Dr. Night enticed him to that room above Britton Chambers's offices?

"As you guess, Mr. Iston, this room is immediately above Mr. Britton Chambers's private office. For some days I have kept close watch on him."

He lifted a small earphone from a hook under the desk and laid it on the blotting pad. From the same place he brought out a head-set.

"This," the Asian touched the headset, "is connected to Mr. Britton Chambers's telephone. He had quite an interesting conversation with his bank manager this morning." He paused and lifted the earphone. "This is the receiving end of a Dictaphone. I regret that Mr. Chambers is away from his office at the present moment. His failure to discover your whereabouts should make his spoken thoughts extremely interesting."

"But," Roy stuttered in surprise, "what's all this about? I followed instructions."

"Did you?" Dr. Night laughed gently. "Your instructions were to follow Mr. Britton Chambers to his offices in this building and deposit this case"—he touched the case Roy had carried—"there."

"I was to follow Mr. Britton Chambers and then the person who took the case of money from his hand," protested the newspaper man.

"So Mr. Britton Chambers instructed you." Dr. Night nodded assent. "But, unfortunately, Mr. Britton Chambers did not allow for a slight alteration in his plans."

"Not by Mr. Britton Chambers." The Asian smiled slightly. "I regret I found it necessary to interfere. But a slight, a very slight, alteration, and—" The smile lingered on the thin lips of the master-crook. For some moments he watched Roy in silence.

"I am to take it, then, Mr. Iston, that you are no party to what proved to be an innocent deception?"

"Deception?" Roy laughed. "Look here. Dr. Night, I don't know what you are driving at. If you want to know, I'm after you, and I've got all the influence and pull of the Mirror behind me."

"But, in this matter, I'm in a fog. Mr. Britton Chambers found out that I was watching Mr. Hofton Wales when he went to his bank to draw the twenty thousand pounds you demanded for the return of his son. He told me of your demand on him, and suggested that when he handed over that brief case to you, or your messenger, that would be the quickest and surest manner of getting on your trail. I agreed. What he made me carry that case for I didn't and don't now understand."

For a long moment Dr. Night sat staring at the journalist. Roy shivered. Those brilliant, burning grey eyes appeared to be reading his most secret thoughts.

"I believe you," the Asian spoke smoothly. "It is just that you should know how you have been deceived."

"Yes, deceived. Do you know that in this case you brought fifty thousand pounds from the Western States Bank?"

"Mr. Britton Chambers brought the money to his offices in the brief case he carried."

"He changed the cases in the bank, giving you the case containing the money. I believe Inspector Frost was in Pitt Street when Mr. Humberston took the case from Mr. Chambers's hands."

"To confuse Mr. Britton Chambers's plans I made a slight alteration in my arrangements. I allowed him to change cases with you although my man stood beside you and him in the bank, and could have interfered. I allowed Mr. Britton Chambers to pass a brief case filled with waste paper to Humberston. All I did was to suggest to Mr. Humberston that he took you for a little walk and then brought you to me, here."

"What matters!" Dr. Night tapped the desk top impatiently. "You want proof. Place your hand upon the brief case you carried."

Almost against his will Roy obeyed. Dr. Night threw open the other case. It contained only the waste paper cut to banknote shape he had seen when he opened the case that morning in his office.

Roy required no further urging. He opened the case and turned out on the desk many packets of bank notes.

"It is not difficult to fathom the mind of a Britton Chambers." Dr. Night laughed gently. "Almost these things"—he touched the earphones—"are unnecessary."

For a time there' was an uncomfortable silence in the room. Dr. Night was staring before him into space. Roy was furious. Britton Chambers had used him, not to trace down the arch-criminal, but to safeguard his beastly money.

Roy would not have cared had the financier fully explained his purpose. He would have willingly lent his aid to convey the money to the financier's offices. But the unnecessary deception irked him and aroused his ire.

Britton Chambers had planned to deceive Dr. Night. The brief case containing the waste paper was to be taken by the Asian's agent. The case of money—Had the man thought that Dr. Night would accuse his agent of stealing the money?

"The man deserves punishment." Dr. Night spoke gently, a slight twinkle in his eyes.

"He deserves punishment." The Asian laughed again. "Mr. Iston, do you know what I should have done had he failed to bring me the fifty thousand pounds?"

"He would have got it in the neck, like Hofton Wales and Albert Wilson," exclaimed Roy.

"Colloquial, but exact." Again the twinkle dawned in the master criminal's eyes. "Mr. Iston, speak frankly. In your heart of hearts you consider that man deserves punishment?"

"Then rest in peace." Dr. Night produced from his pocket a small case and pressed the spring. "You recognise this?"

"The Shah's Eye." With a snap the Asian closed the case. "But three days ago Britton Chambers's agents brought this jewel into Australia. To-day it is mine."

"It is mine," the Asian reiterated. "The soul of that jewel would perish in that man's hands. But enough of that. I must safeguard you."

Swiftly the Asian emptied both suitcases. In the case Roy had carried he stowed the waste-paper.

"Go down to Britton Chambers's offices," he commanded. "Give him this case. It is the one you carried. He is in. Give it to him. Remember, it has contained nothing but this trash."

CHAPTER XXI

MECHANICALLY Roy turned and walked into the outer office, closely followed by Humberston. As he passed out into the corridor he glanced at the door. The glass was clean, no lettering appearing on it.

"Put on for your benefit." The man grinned. "And, by the way, there's no need to come back, You won't find any one here."

Roy went down the stairs to Britton Chambers's offices. Immediately his name was taken in to the private office the financier came out.

"Have you got it?" he asked eagerly. On receiving Roy's nod of assent he motioned towards his room. Roy followed him and placed the brief case on the desk. The man heaved a sigh of relief.

"Frost met with an accident crossing the road to collar the man who took the case from you." Roy spoke briefly. "I had to take up the chase. He led me a pretty dance."

"The second floor." Roy appeared to consider. "Now I come to think of it, he must have gone into an office immediately over here."

"There was a name on the door. Dr. Night; yes, that's it. Funny there should be a dinkum Dr. Night in this city."

"I don't believe you!" The financier was holding on to the edge of his desk. "You're lying!"

"I beg your pardon." Roy stiffened. "Thanks for a chance that never came off. Oh, by the way." The newspaper man pulled a few notes from his pocket. "Here's the money from the cheque you gave me to change. Good-day!" He turned to the door.

"Here, wait a moment." Britton Chambers was fiddling with the brief-case Roy had brought with him. "Perhaps I was hasty!"

The man's jaws fell apart. He had opened the brief-case and was staring at the collection of waste-paper.

"You knew that case contained no money." He spoke pointedly. "I found it at the Mirror offices this morning and-examined it there. I have carried it about with me all day. I believe you put that paper in that case yourself, Mr. Britton Chambers."

"But—" The man hesitated. He could not tell the newspaper man that in the bank he had changed the two cases.

"What is the matter, Mr. Britton Chambers?" Roy tried to infuse concern into his voice. "Don't you feel well?"

"Quite a sum, isn't it? Well, you might have been hit for more if you hadn't been sensible enough to meet Dr. Night's first demand."

"Mr. Hofton Wales lost his son; Mr. Wilson, his picture. By the way, Mr. Britton Chambers, there was a piece of news in one of the newspapers the other day. It was reported that you had purchased the famous ruby, the Shah's Eye. Has it been delivered yet? When you get it don't forget the Mirror. We would like to send a photographer down to picture it."

"Worth quite a lot, I believe," Roy went on, tormentingly. "You were wise to satisfy Dr. Night. He might have taken a fancy to that jewel. Those Orientals are fond of gaudy stones."

"Sorry our little plan failed." The reporter picked up his hat. "Can't hope for success every time. Perhaps it would have been better if I had stuck to Hofton Wales's track. I might be on Dr. Night's trail now."

With careless nonchalance he strolled through the outer offices to the corridor. He waited a moment to be sure Britton Chambers did not follow him, then raced to the floor above.

The door which had borne the legend "Dr. Night" was fastened. Roy knocked, but there was no reply. Then he noticed an envelope stuck to the glass. He bent and examined it—and read his own name on it. Eagerly he tore it from the door. The enclosure was short and significant.

Received from Hofton Wales the sum of twenty thousand pounds for the discovery and return of his son, Herbert.—Dr. Night.

Roy laughed. Dr. Night had caught him napping again. When he had left Britton Chambers's office he had determined to go to Mosman and watch Hofton Wales' house. Now he could do nothing. His plans had all failed, and mainly through the greed and duplicity of the man he had sought to protect.

He ran down the stairs and out into Pitt Street. On the pavement be looked up into the sky. High over the streets hung an aeroplane. High as it was. Boy could see it had no propeller.

He turned and hastened down to the harbour—the direction in which the stolen plane was making. There he had a better view. The 'plane had lost altitude considerably, and was now only a few hundred feet up. Above the roar of the city traffic he could hear the low, sinister sound of the gravity plates; the sound that had won for the machine the title of "Whispering Death."

Why was the 'plane hovering over the city? Immediately followed the thought—if he could trace it to its hangar. He felt in his pockets, and sighed in relief. He had quite a fair sum of money on him.

On its previous appearance over Sydney the aeroplane had come from and returned to the eastern seas. Then was its home on some island off the coast, or on the mainland? Had the 'plane come from the continent, circled high, out of sight, and then flown in from the sea?

That was possible. Roy hailed a taxi. "Out to South Head, as quickly as possible," he ordered.

Throughout the journey he watched continually for the 'plane, but could not see it. At South Head he alighted and told the driver to await him. He went to the lighthouse and routed out Jack Seeman.

"Ask me something easier." The newspaper man laughed. "I saw it. No, I'm not pulling your leg. I saw it twice, and the second time it was sailing low."

"That's a mystery, sure enough." The old sailor shook his head. "Now, t' other night it sailed in from the seas."

"You said that before." Roy laughed. "I'm not a sailor. Point, my jolly salt, point!"

"May have been," Seeman admitted. "I only saw it when it was high overhead. What's that?"

The strange whispering sound with its queer note of warning became audible. Roy and the sailor looked up. Only a few hundred feet above their heads hung the mystery aeroplane.

"Lord Almighty!" Seeman gazed awestruck at the machine. "Why, man, it hasn't got a propeller."

For some minutes he watched the 'plane carefully, wondering what should be his next move. The 'plane hung immediately above the lighthouse, then commenced to drift slowly out to sea.

Roy looked around him. He stood on a high foreland, commanding a fine view over land and sea. Yet he felt he was not high enough. His eyes fell on the lighthouse, pointing whitely up into the blue southern sky.

"I tell you, 'tain't allowed." The sailor spoke emphatically. "Visitors ain't allowed in the lighthouse at all, at all."

"Oh, well." Roy shifted his attack "Guess you've seen a bit Of life, Mr. Seeman."

The old man looked at him suspiciously for a moment, then the temptation to romance became too strong. Roy watched the aeroplane slowly disappearing out to sea.

"Haw, haw!" Jack Seeman was rolling back his head, in laughter. "You writer fellers—"

"I'm not joking." Roy was desperate. "Listen, Seeman, to steal a ship is piracy?"

"Well, that aeroplane that passed over our heads was stolen. I've got to find out where it came from and where it is going to. Take me up the lighthouse. I can see from there."

"You've no sympathy with pirates. No honest sailor has. Look here, Seeman." Roy shook the man in his excitement. "I've just got to find out."

He hobbled towards the lighthouse, Roy following closely. Slowly and painfully he toiled up the steps. Roy cursed under his breath. Would he be too late?

On the gallery surrounding the lantern, Roy peered out to sea, hope fading from his heart as he swept a clear sky.

"There she be!" Seeman's finger pointed slightly south of east. "She's picking up speed. She's coming back!"

Roy could see the aeroplane now. She had drifted far out to sea; then, picking up speed she swept to the southwards, circling in a wide sweep towards the coast.

"Know where's she's heading for, Seeman?" The newspaper man almost shouted in his impatience.

"Might guess." The old man answered imperturbably. "Yes, that might be it." He paused and squinted at the 'plane. "Come down to the locker room, young master. I think I knows something."

CHAPTER XXII

ROY returned to the city late that afternoon, undecided whether he had spent a profitable day or not. His conversation with the lighthouse-keeper had resulted more indefinitely than he had expected. All he had learned was that while the Whispering Death came over Sydney from out the sea and departed in a like direction, the 'plane eventually returned to land.

Somewhere down the south coast, between Port Hacking and Kiama, had been Seeman's judgment. It was a long expanse of coastline to examine—in some parts lonely and indented with numerous bays and coves. A wonderful hiding-place for anyone who had anything to conceal.

Dr. Night had taken Halliday's gravity 'plane there. In all probability he had established a workshop, where he was duplicating the machine.

What was the Asian's object? Hardy had said that he was the last descendant of the reigning house of some forgotten Central Asian Empire. He was obsessed with the idea that it was his fate to recreate the old glories of his race.

Was that true? Roy had seen the man only twice. Each time he had been impressed by the wonderful powers possessed by the man. He had seen him so dominate a roomful of men that when he had departed no one could exactly recount what had happened.

There could be no doubt but that Dr. Night had some project in mind for which he proposed to use the Whispering Death. That project could only be blackmail on a wholesale scale—or conquest.

But, if Dr. Night was constructing a fleet of gravity 'planes, he must have some workshop fitted with the necessary tools and workmen. Sir Max Vanderlere had solved a similar problem by buying a controlling interest in the aeroplane factory at Ashfield.

It was possible Dr. Night had taken the same course. He might have his 'planes built in some established factory, by contract; but that would cause comment and talk. He could have the 'planes constructed for him in sections, at separate factories and then assemble them at his secret base.

Either of those plans would give him the gravity-'planes he required for his purpose, whatever it might be.

Arriving at the Mirror offices, Roy wrote a terse account of the day's happenings, then went to the library and collected the directories and books on aerostatics he could find.

The directories offered him little help. There were six aeroplane factories in Australia, of which four were located in New South Wales. One of these was under the control of Sir Max Vanderlere.

Roy went in search of Hardy. The chief sub. had not yet arrived. Kingston, who was deputising for him, said that he was not expected until a late hour.

Roy returned to his directories and searched further. Two of the four aeroplane factories were situated on the plains of the Central Tableland, one was at Goulburn and the fourth at Ashfield. So far he had not made any progress.

The journals did not help; the only item of interest that the newspaper-man could discover was that near Port Hacking lived Frederick Hanson, perhaps the most famous aviator of the time. The article mentioned that Hanson had a small workshop in the grounds attached to his house.

Roy telephoned Hanson's house. The aviator was absent from home. A woman's voice informed him that Mr. Hanson's workshop was used solely for his own aeroplane repairs and experiments.

Again the journalist turned to the telephone, putting through calls to each of the aeroplane factories in the State. His query was always the same. Was that factory making parts of 'planes containing any peculiarities, for any person or firm? In every case he obtained a negative answer.

For more than an hour Roy wandered aimlessly about the Mirror building, wrestling with his problem. He could find, no solution. So far as he was concerned he had run into a dead end.

While Roy was pacing the big reporter's room Alphonse Thomas's door opened suddenly, and the managing editor peered out. He caught Roy's eyes and beckoned.

"Well?" Then without waiting for an answer. "Good story, today. That Britton Chambers got what he deserved."

"Up against it, sir." Roy tried to smile. "I thought I was on the track of Dr. Night, but Chambers queered my game."

"Too bad." Thomas leaned' back in his chair, crossing his hands before him. "Tracking Dr. Night is like tracking a bird through the air, after it is out of sight Got any ideas?"

"Not much." Roy scanned the few lines. "I don't trust these men. They're not interested in bringing Dr. Night to bay, only in safeguarding their filthy money."

Yet he took note of the content, of the letter. It was the usual demand for money from Dr Night, and addressed to Anton Fairman The only peculiar thing was that the Asian had reduced his demand to ten thousand pounds—yet Fairman was reputedly much wealthier than any of the three previous men the crime-master had blackmailed.

"Tell me the secret behind Albert Wilson's painting and I may strike a clue," the newspaper-man exclaimed suddenly.

"What's that?" Thomas sat up, alert. "Britton Chambers infers that Wilson's Murillo is not genuine; yet the man valued it at £50,000. That's the price Dr. Night demands for its return."

"Umph!" The managing editor sat forward with his chin cupped in his palms, Ills elbows on his desk. "Roy Iston. I believe you've struck something."

"Then I'm particularly dense, sir." Roy laughed. "I believe there is a secret attached to Wilson's Murillo but I haven't a clue to it yet."

Thomas reached for the telephone and asked for a connection to the Hotel Zenith.

"Mr. Albert Wilson in his suite?' he asked on the acknowledgment of his call. He waited a moment, then spoke again.

"Mr Wilson, we have been informed that you have paid Dr Night fifty thousand pounds for the return of a Murillo painting missing from your Moss Vale residence. Is that true? Not paid yet. Waiting to hear from Dr Night. Oh, then you intend to pay? How? Oh, thanks!"

The newspaper-man shook his head. He had not had the heart to go out and visit the inventor. To be in that house, where he had spent so many happy hours with Ruth would be torture.

"They didn't leave it to someone else to look after you—when you had that accident."

"Don't forget that Dr. Night is pressing Halliday for the secret formula of the gravity plates," continued the managing editor. "Hardy's stiffened him a lot to resist, but the pull of his daughter's captivity is wearing the man down."

"Of course. It's asking a lot, y'know, but if Dr. Night gets a fleet of those gravity-'planes in the air there'll be hell to pay in this little old world again."

"I do." The managing editor pulled a map from under some papers. "Look here. Here's the district where, Hardy claims, exists Dr. Night's deserted city. Let that man locate himself there and have control of a fleet of those gravity-'planes and he will raise hell."

"Russia will object. The Soviet will not stand for an autocratic Empire being built in their territory. They will send troops to hunt him out Now, look! That district borders the Chinese Empire. All Dr. Night has to do when he finds Russia intends to attack him is to stir up the Chinese against himself. For years China has been developing a military spirit. They'll have a shot at him. That means invading Soviet territory. Russia and China will tangle and Dr. Night, from the air, will play a merry tune on both."

"More than that, you young goat!" Thomas exploded "Run your finger south and you will come to India and beside it Afghanistan We're interested in India, and India in Afghanistan. Let Dr. Night light the bonfire in Semarechensk and a thousand to one the northern Indian tribes will not be able to resist burning their fingers Sure as fate, they'll attack some Afghan tribes they particularly dislike, then—"

"Very well put, sir." Roy looked up to see Hardy standing in the doorway "You seem to have developed the point I made the other day, sir."

"Developed, hell!" Thomas growled. "It developed itself. 'Sides, I've had Professor Evans up here. He wasted quite a lot of time—but completed my education."

"Good." Hardy turned to Roy. "The librarian's got a grudge against you. young man. Says you've given her half-an-hour's work clearing up your mess."

"Good lor'!" The reporter looked conscious-stricken. "I wandered away without thinking."

"Searched without thinking, you should say." Hardy laughed, good-humouredly. "You were on the right tack, Roy, but you didn't go far enough."

"She told you that Frederick Hanson was away—didn't say where; didn't mention who she was."

"She told me the same," Hardy drawled. "But I was more inquisitive than you. I wanted to know just where Frederick Hanson was. As the lady could not, or would not, inform me, I made a few inquiries. Fred. Hanson was last seen, by the postman, in his garden. His car is in the garage and he didn't leave by train. That tell you anything?"

"Seeman said the 'plane came in over land just, below Port Hacking!" exclaimed Roy.

"A statement good enough for any good newspaper-man to theorise on," Hardy laughed. "By the way, Roy, Halliday wants to see you. Seems to think you've neglected him of late."

"I'd go out tonight if I were you. Dr. Night promises to pay Halliday a visit at an early date."

CHAPTER XXIII

FOR a full moment Roy stared at his fellow journalist. Dr. Night promised to visit Halliday! Then the Asian had determined to press for the formula for the gravity plates! And Ruth was in his hands! He turned blindly to the door.

The reporter nodded. In the street he found the car and slid behind the steering wheel. He turned out of Phillip Street into King Street. Taking the back way, via Cathedral Street to King's Cross, he let the car out. In the clearer streets beyond the Cross he stepped savagely on the accelerator.

He had to get to the Halliday house before the Asian That fact pressed on his brain. He had to be there before Dr. Night—or Ruth was lost.

Halliday would be divided between his secret and his love for his daughter. He might try and temporise—and Ruth would be lost. The inventor did not know the relentless purpose, the fixity of idea, of the Asian. Dr. Night would act—not against Halliday, but against his daughter.

He skidded from the main road into the by-street that led to Halliday's home. Some hundred yards from the house he pulled up and looked about him, cautiously. The road was deserted. He started the machine again and drove past the Halliday's home, pulling up some two hundred yards from the gate. He alighted and left the machine, walking back to the gate.

Halliday would be In the laboratory at the end of the garden. Avoiding the front windows, Roy crept around the corner of the house and sped through the shrubbery to the workshop.

"Come in, boy!" As he entered the door the inventor rolled his chair forward to meet him. "I thought you had deserted us."

"Not that." Roy spoke lightly, intent on keeping from the inventor's face the lines of pain and worry. "I've been busy, trying to get on the tail of that scoundrel. Bob Hardy told me—"

"A good friend, Robert Hardy." Halliday's face lightened. "He has told me something of your work—the work you are doing for us; to free the world from a menace. He and Mrs. Hardy—"

"She is here now. When she heard that this—this Dr. Night had taken Ruth, she came. Mary—I don't know what my poor Mary would have done without her help and comfort."

"So he said. Thank God Mary did not take the message over the telephone. Mrs. Hardy was here. She took the message and brought it to me."

"He knows that I dared not do that." The inventor shook his head. "He holds Ruth—and would make her suffer for my fault."

Hardy knew that Dr. Night was to come to Vaucluse that night. Had he told Frost? If he had then the police were in the neighbourhood.

But this time there must be no mistake. Dr. Night must be captured without fail. One slip and he would get away; perhaps to take some horrible revenge on the girl.

"What can I do?" The inventor smiled, wanly. "I am an invalid and he is a man endowed with some miraculous power." He motioned towards the table, by which his wheeled chair stood. "There is what he comes for. Let him take it and give me back my girl."

Roy glanced curiously at the table. On it lay an ordinary envelope and across the envelope a revolver.

"Either for him," the invalid whispered. "I have only one condition. I will give him the formula but before he takes it my girl must stand in this room. If he agrees, then he takes the envelope. If he will not agree—" The man straightened himself. "—then he will die."

The words were spoken simply; so simply that a choke rose in the journalist's throat.

For a long minute Halliday mused. Then he turned to the table and took the envelope.

"You are right. He will deceive me. He will release Ruth, but he will take the formula and me."

Roy read the simple formula that applied to an amalgam of metals which overcame the earth's gravity. He wondered at its simplicity. A bare dozen lines, a few common numerals and chemicals. But, by their combination, they gave the solution to a secret ages long and often sought.

A few minutes and Roy handed back the paper. Halliday enclosed it in a new envelope and sealed it again.

For the moment the inventor was perplexed. Then, driving his chair to the other end of the room, he picked up a small earthenware crucible. With a sharp instrument he worked on it for some minutes.

"The telephone, Roy," he exclaimed as he placed the crucible with its fellows. "Tell Hardy that if anything happens to you and me to look in the cup in the laboratory."

Roy seized the instrument and dialled the Mirror number. He had to wait for some moments to get the connection to Hardy's desk.

A tap came at the door. Halliday waited an instant before replying, but the electrical power was cut from the door. Suddenly it was pushed open and Dr. Night stood in the opening.

"Hardy, is that you, Hardy!" Roy had at last obtained the connection. "Listen! What you want is in the cup. Understand? In the cup."

"I am afraid that I do not understand, Mr. Iston." Dr. Night spoke with a slight smile.

"I am not afraid of you, Dr. Night," Roy laughed slightly. "You came here to rob Mr. Halliday."

"I promised Mr. Halliday a half-million pounds for his gravity 'plane. It is worth it. Here is the first instalment—a hundred and twenty thousand pounds."

"Mr. Halliday understood that the money was to come from the British or Australian Government. That would be clean money; money he could handle. This is dirty."

"All money is dirty; money is all evil. Men commit sin for it; suffer everything to possess it."

"And counterfeit money, as there are counterfeit men." Again the doctor shrugged. "Mr. Halliday, you know what I have come for. Will you do as I request?"

The Asian made a move towards the envelope, but Halliday grasped the revolver lying upon it.

"Bring Ruth into this room. Free her from your malign influence, and that envelope containing the formula' for the gravity plates is yours."

"But the secret makes you important." The Asian smiled secretly. "Until my hour comes—until I have proved your claim and am ready to leave Australia—I must ask Mr. Halliday and Mr. Iston to accept my hospitality."

The Asian stepped to the door and whistled a low, sweet note. In a moment a woman came into the moonlight on the lawn, walking towards the laboratory. At the door she hesitated, looking directly at the Asian.

The arch-criminal breathed a low word to the girl. Her body stiffened, then relaxed. She looked around her wonderingly.

The great door of the laboratory swung shut. The Asian turned, to see Roy standing by the great switchboard, pressing down a lever.

"The door is shut and electrified." Roy laughed triumphantly. "The windows are impassable. Mr. Halliday fortified well when he built this place to hold his secrets."

"The long trail ends." he continued whimsically. "Dr Night is at last, a prisoner."

CHAPTER XXIV

A FAINT smile lingered about the corners of Dr. Night's lips. He betrayed no uneasiness, his eyes wandering from Roy's triumphant air to the switch on which his hand still rested.

Halliday had snatched up the revolver and held it lying on his lap. A faint gleam of hope was dawning in his eyes. Would the reporter save the secret of his mystery 'plane? Almost he believed so.

Awakening from the brain-sleep in which the Asian had held her. Ruth had run to her father's side, and knelt by the wheeled chair. Her eyes were turned, wonderingly, on Roy.

"A stalemate." Dr. Night spoke evenly. "You have electrified the defences of this laboratory, and I cannot get out. Has Mr. Iston forgotten that he also holds prisoner Mr. and Miss Halliday—and himself?"

"The return of the aeroplane you stole and your solemn pledge for yourself and your gang that you will not molest Mr. Halliday and his family further."

"Nothing." The reporter threw back his head proudly. "I am not afraid of you, Dr. Night."

"No, you are not afraid of me." The Asian spoke gently, almost sadly. "Twice before have I seen men who feared neither me nor the powers I control. But—" He paused and bowed his head a moment in thought. "But they had not your courage. Hold up your hand, Roy Iston!".

Instinctively Roy obeyed, holding up his left hand above his head, the palm facing the Asian.

For a long moment. Dr. Night stared at the raised palm. Roy felt a strange tingling in the centre of his palm. It crept up his fingers until his hand felt as if it was on fire.

From the tip of each finger glowed a strong red light, dancing and quivering in the still air of the room. As Roy glanced up at his hand the light changed to yellow, and quickly through shades of green to a beautiful limpid blue.

The young man laughed, lowering his hand to more closely examine the strange light that poured from his fingertips. He passed his right hand across his left and felt no beat. His left hand felt deliciously cool and clean.

"Some conjuring trick. Dr. Night?" he asked laughingly. "Is this a time for parlour magic?"

"Mock not." The Asian's words held a deep note. "Pray to the gods that never shall the blue leave you."

"The personal aura?" Roy lifted his hand and examined the light-still more closely.

Almost without thinking Roy extended his left hand towards the table on which stood the little model of the Whispering Death. The model rocked and quivered.

Automatically Roy willed the little machine to rise into the air. To his utter astonishment the machine rose, wheeling and diving in the direction the newspaper man's hand pointed, When he lowered his hand the miniature aeroplane came to rest again on the table.

"The gods will it." Dr. Night bowed his head. "Roy Iston, we shall meet again. Pray they who rule that when that day dawns the blue light is still with you."

The light died slowly from Roy's fingers, leaving permeating his whole being a sense of contentment and comfort.

For a moment there was silence. The Asian stood before the electrified door. Through the room swept an air of impending happening.

A strange grey mist emanated from the Asian. It spread, enveloping him as in a cloak. Roy gasped. He could no longer see the door. Even Dr. Night was fading from his sight.

For more than a minute the grey mist enveloped the door and man. Roy backed to the switchboard, firmly holding in place the lever which controlled the door. The mist slowly dispersed, and where the mystery man had stood there was nothing.

Roy threw down the switch and darted to the door. It was fast shut and safe, save that the electric current did not cover it. Roy knew that he had but to force the lever back into place and the door would be finally safeguarded But, where was Dr. Night? Roy turned and looked at the inventor and Ruth. They were staring at the fastened door, disbelief in their eyes.

Had Dr. Night passed through the closed door? There was no other explanation—yet that was impossible.

"Not impossible." Halliday answered the newspaper man's unspoken thoughts. "There is such a thing as the fourth dimension, though we, of the white races, hardly know the name of it yet."

"I saw the mist gather, and Dr. Night became part of the mist." Ruth spoke slowly.

"He left the formula." Halliday motioned to the letter which lay on the-table beside him.

Roy stretched out his hand to pick up the envelope, but it slipped from under his fingers. Again he attempted to grasp it, but unavailingly.

The envelope slid along the table to the edge and fell to the ground. The newspaper man stooped to pick it up. In his hand it commenced, to twist and twirl. Suddenly it escaped his grasp and glided through the air to the door, on which it hung.

Again Roy sprang towards it, but drew back as the cold, grey mist gathered around it. As he watched the envelope grew faint in outline and gradually dissolved into the mist.

"Again the fourth dimension." Halliday laughed, almost bitterly. "Now Dr. Night has the formula."

Roy went, to the switchboard and released the door. As it swung open he noticed that a man was standing under the trees on the right of the lawn, watching the laboratory door. Awaiting a moment when the moon was dimmed by a passing cloud Roy slipped into the open. Keeping in the shadows he came up behind the watcher.

"Moon-dreams!" Roy laughed lightly "I walked out of the laboratory, through the door, but a couple of minutes ago."

"He was with us in the laboratory." Roy spoke with careful carelessness. "He came out a few minutes before I did."

"But I've been watching that door," protested Frost. "I've never had my eyes off it."

In a few words Roy described the scene in the laboratory. Frost listened in silence, his face expressing disbelief. Gradually a conviction grew that Roy was recounting something that had actually happened. When the newspaperman concluded there was a long silence.

"So Miss Halliday is back home again," the detective said at length. "Where has she been?"

"She does not know." Then, seeing disbelief in Frost's eyes, he continued: "Man, if you had seen her come here you would not doubt. She was free, absolutely free and alone, yet she came obedient to that fiend's word. She knows nothing. From the moment he took her from this house neither time nor place has had any meaning to her."

They had strolled to the laboratory door. Ruth was standing by her father, talking earnestly. When the two men entered she looked up at the reporter with a bright smile.

"Mr. Halliday turns night into day, but you should not." Roy took Ruth's hand gaily. "In a couple of hours a new day will dawn and then—" he paused. "Before then Frost and I have to get back to the city."

"But you will stay here, Roy." For the first time the girl used his given name. The intimacy sent a little thrill through him. "I—I don't think I shall rest unless you are near."

"Your room is ready for you, my boy." Halliday added quickly. "I too, I think, will rest easier if you are near to protect my dear ones."

"I'm going to support that." Frost interjected. "There's no reason why either of us should leave the place to-night."

"Which would be unoccupied, young lady." The detective laughed. "A rug and one of the cane lounge-chairs on the veranda will fit me. I'm going to watch—not sleep."

The detective had his way. Laughingly driving, Halliday and his daughter before him, Roy made, for the house. In the hall he held Ruth's hands for some moments, While saying "good-night." Suddenly she took his left hand in hers, examining his fingers, curiously.

"Strange, wasn't it." Roy was willing to talk on any subject to prolong the intimacy of the moment. "What did it mean?"

"The 'blue' light did not burn—the 'red' did!" For a brief moment the girl looked up at the man she now knew to be her lover, then turned and disappeared into her mother's bedroom.

Roy found the Inspector curled up in a deck-chair on the back veranda, a thick rug wound round him. The journalist hesitated. He did not feel like being alone. With a muttered word he went to his room and pulled a blanket from the bed. Lying in a chair close to the detective, with his pipe in full blast, he felt more comfortable.

"'Um. He'll be out here at dawn." Roy laughed slightly. "You see, Frost, when I knew Dr. Night was about and that there didn't seem to be a hope for us to get away, I got Halliday to conceal the formula of the gravity plates in the laboratory; then 'phoned him a clue to the hiding place. He'll be out here at dawn, I'll bet."

"He knows Dr. Night." Roy paused. "Hardy's no fool, old man. He knew when he got my message that he had been elected our last hope. He had to find that formula and take it to Sir Max."

"Just think what the position would have been if he had come out here, at once, to find the formula. He would have guessed that Halliday and I, once Halliday had surrendered the formula to Dr. Night, would plan to get it in Sir Max's hands. If that proved impossible then Dr. Night would have the formula, Halliday and myself, and—" For a long moment he paused, "and with the only fleet of gravity 'planes in the world needn't confine his activities entirely to Central Asia."

"That—and other things." Roy nodded gravely. "Frost, do you know, I think I have a clue to Dr. Night's headquarters."

Before the detective could answer a low, sinister whispering grew on the air. The two men looked at each other in fear and amazement. The sound grew louder until it filled space, vibrant and unutterably evil. Frost shivered. Not by any means an imaginative man, the mysterious whispering filled his mind with thoughts of violence and death.

Suddenly he sprang to his feet and seized the detective, pulling him into the passage and flinging the door shut.

The sinister whispering grew louder, poised, it sounded immediately above the house. For a long moment it lingered, then slowly died into the distance.

Then the house rocked beneath them to the violence of a terrific explosion. The detective wrenched his arm from Roy's grasp and flung open the door. Where the laboratory had stood was now a huddle of broken masonry and burning timber.

"Lor'!" Roy muttered. "Dr. Night went to a lot of trouble to destroy a cup—a three-inch crucible."

CHAPTER XXV

IT was some time before Frost and Roy could calm the household and send them back to bed. Doris Hardy absolutely refused to return, and elected to sit up with the two men and await her husband.

For most of the time they sat in silence, each engrossed with their own thoughts. Roy now knew that the danger was very real. Dr. Night would not have destroyed the laboratory unless he was very certain that neither Halliday nor he could escape him.

The Asian now knew that the inventor had confided the secret formula to Roy. He knew, or had guessed, that somewhere in the laboratory was hidden a copy of the formula. He had taken immediate steps to destroy it.

Now he would strike, with all the evil powers he commanded, to capture them. That accomplished, he would have complete and sole control of the new power. And, with that power in his hands, to what lengths could he not go? The dream Of the re-creation of his forefather's empire would crystallise into a dream of world dominion.

In a low, sing-song voice he commenced to recite the secret formula. Doris and Frost looked up, inquiringly. Roy did not explain immediately.

"Listen! Learn this." Again he went over the formula, line by line, setting the words to a simple catchy tune. Doris joined in almost at once, to be joined a little later by Frost's deep bass. For more than a quarter of an hour Roy led them in continued repetition.

"You've got it now." he said. He then repeated his account of the scene' in the laboratory. "Dr. Night blew up the place to preserve the secret of the formula to himself. He knows I know it, therefore he, will strain every nerve to get me in his power."

"But I'm staking on the fact that he believes that Halliday will not entrust the secret to anyone else. I don't think he would, myself." Roy smiled. "That's why I'm teaching you two the formula. Doris, directly you get in touch with your husband, teach it to him. Let him take it to Sir Max, and tell them to push on with those gravity 'planes with all speed. Understand?"

"Can't understand why Dr. Night didn't blow up the laboratory when you and Halliday were in it?" Frost questioned. "He could have included me in the holocaust."

"Not a killer?" Frost was amazed. "Why, I hold a warrant for his arrest for murder."

"I should have said a shedder of blood," Roy amended. "Have you noticed, Frost, that in all cases where death has occurred through Dr. Night no blood has been shed. It's—it's—I believe it's against his religion."

"Damned funny religion, to differentiate between kinds of killings." The detective paused a moment. "What's the next step, Roy?"

"Wait for Bob Hardy." Roy looked out on the lightening sky. "He should be here any minute now."

Ten minutes later a man walked around the corner of the house on to the lawn and stopped suddenly at sight of the wrecked laboratory. Doris gave a little cry and ran down to him.

A minute and the man and girl mounted to the veranda. Before Roy would answer questions he insisted on Hardy learning the secret formula.

"That's a relief," he said, when Hardy was letter perfect. "Get that to Sir Max and we're all safe. By the way, Bob, how's the Ashfield factory protected? Can't understand why Dr. Night hasn't had a shot at it."

Hardy laughed quietly. "Two days ago Halliday sent down a complete set of plates. Now one of the 'planes hovers over the factory night and day—a machine fully armed. It would make mincemeat of the 'plane Dr. Night stole."

"Aviators and their crews, mostly. Sir Max has had a body of men, many of whom saw service in the Great War, organised for the past week. They're to take shifts in the 'plane overhead and put in other time as ground guards."

"Three of them completed and awaiting the gravity plates. Three more will be ready in a couple of days. They're easy to build," continued the newspaper man. "There are no engines and gadgets of that sort to worry about. Easy to fly, too. Why, I went up in the guard 'plane yesterday, and although I don't know a Joystick from a walking-stick flew, the machine for over an hour."

"Why has he let Ashfield alone?" continued the detective. "I don't quite cotton to Hardy's explanation."

"Dr. Night let them build the ships in peace," interposed Doris, "because he knew that Mr. Halliday alone made the gravity plates. He thought he would be able to steal the aeroplanes when they were ready, awaiting the gravity plates."

"Something like that," acknowledged her husband. "Yet he slipped up badly in one instance—over Whispered Death the Second. Wonder how he made that mistake?"

"What's the next move? No good me attempting to advise. In this game I'm trailing along in the rear."

"Dr. Night's there—or at least a clue to him is there," the young man explained. "Remember what you told me yesterday?" he added, turning to Hardy.

"You won't find him there," he said. "He's attending to Anton Fairman to-day, in the city."

Roy uttered a little exclamation. He went into the house to his room, returning with a bundle of bank-notes.

"Dr. Night brought these to Halliday last night," he explained. "Part payment of the half-million he promised for the 'plane. Queer cuss, isn't he? Steals a thing and then goes to a lot of trouble to persuade a crowd of uninterested people to pay for it. Something like shaking hands with oneself or making a noise while eating, to show politeness."

"What am I to do with them?" The detective expressed surprise. "Divide them between Wales, Wilson, and Britton Chambers?"

"They belong to the three men." Doris spoke softly. "The money should be returned to them."

"They deserve to lose it," said Hardy. "'They didn't help one iota to guard themselves against the blackmailer."

"I'll take this to the Commissioner." he said. "Tell him it's loot recovered from Dr. Night, but not where it originally came from. The three financiers will have to prove it belongs to them, and, although they may eventually do so. Sir Henry won't make it any too easy for them."

The men nodded agreement. A stir within the house showed that the night had passed. Doris left the men to join Mrs. Halliday and Ruth to help to prepare breakfast.

Immediately after the meal the party broke up. Frost. Hardy, and Roy went to the city, first placing Halliday in Doris's car. It had been decided, during the meal, that now the laboratory was destroyed no need existed for the Hallidays to stay at Vaucluse for the present. Doris immediately claimed them as her guests. From the Potts Point house Hardy could frequently take Halliday to Ashfield to supervise the final preparations of the 'planes.

In the city the three men parted at the Mirror offices. Frost went to Police Headquarters, leaving the two journalists standing beside Hardy's motor car.

"Send me down one of the youngsters who can drive. He can take me out to Port Hacking and leave me there."

"Good-o! Take care of yourself, son. There's a little lady at my home who will require a pile of questions answered, if you' don't show up soon. For my grey hairs' sake, spare me."

He grinned broadly at the sight of the rich colour that flooded Roy's face and disappeared through the swing doors. A few minutes later a youth came out of the building.

"Then hop in. You're elected chauffeur. Port Hacking, please, and see how many summonses you can collect on the way."

Pat White was a good, but somewhat reckless, driver. He had a fine car under his hands and used it finely. At a word from Roy he came to a halt some distance from the town. The newspaperman alighted and went into a cottage to inquire directions.

From the information he received Frederick Hanson occupied a large, old-fashioned house, standing in large grounds, on the opposite side of the town. Roy returned to the car and directed Pat. A few moments and they were within sight of the house.

Roy looked at the place curiously. Of two stories and built of old grey sandstone in the early days of the settlement. A couple of hundred yards from the house stood a large low shed. He guessed them to be workshops.

Had Dr. Night occupied this place to build his fleet of gravity 'planes? The place would be ideal for the purpose. But if Dr. Night had taken possession of the house and grounds what then had happened to Hanson and his family? Were they prisoners of the Asian?

Instructing Pat White to keep out of sight, up a nearby lane, and to have the machine in readiness for a quick getaway, Roy cautiously approached the workshops.

There seemed to be a number of men about, very busy over something. Roy drew nearer, taking advantage of every piece of cover.

The men were Chinese! Roy stared in amazement. For a long time he watched, trying to estimate the number of men about the place. He thought fifty.

A white man came from the big house down to the workshops. Roy recognised him. Dr. Night had called him Humberston in the offices in Bramston Buildings.

Then his and Hardy's hunch had been right. Dr. Night had taken possession of Hanson's house. What had the arch criminal done with the aviator and his family?

Humberston shouted a command and the great doors of one of the sheds rolled back. A group of men entered the building. Presently they rolled out into the open a huge aeroplane.

CHAPTER XXVI

ROY gave a low whistle. He watched the men drag the huge machine into the open. Humberston climbed into the 'plane and appeared to be examining it. He called to one of the Chinese, who joined him in the cockpit.

Had Dr. Night another aeroplane ready to take the air? That was impossible! Had he dismantled the gravity plates from the small machine and fitted them into this monster? But that would be impossible in the time. The smaller machine had flown over Vaucluse that morning and dropped the bomb on the laboratory! Even with his large army of workers he had not had time for that task. Then, there was the doubt if the plates from the smaller machine would lift this monster.

For some time the men busied themselves around the interior of the machine. Then Humberston descended to the ground and walked to the house. Roy noticed that he carried a plan in his hand. Now he understood. The man had been examining the connections between the machine and the gravity plates.

He waited for some minutes in the shelter of the bushes, after the Chinese had wheeled the machine again into the shed; then crept to the road. In the lane he found Pat White and sent him into the city with a hastily scrawled note for Hardy.

When the car had departed. Roy experienced a sense of loneliness. The township was hidden from sight in a fold of the ground. There were only two houses in sight, widely spaced from each other. The big house, owned by Frederick Hanson, dominated the countryside.

Where was Frederick Hanson? Bob Hardy had said that the aviator had disappeared. Then the only solution, in view of what he had just seen, was that Dr. Night had captured him and his estate. The newspaper-man found a sheltered spot and settled himself for a long wait. Hardy would communicate with Frost.

It would take time to organise a police attack on the house. They might not arrive at Port Hacking until late in the evening.

Roy looked at his watch. It was after one o'clock and he had not eaten since the early breakfast at Vaucluse. It would be ridiculous to hang around the house all the afternoon. He would go into the town and get something to eat.

He sauntered down the road, slowly. A loose dirt road, it plainly bore the impressions of Hardy's car tyre. Roy followed them idly. Pat White was a good fellow and would make all haste to the city. Hardy would—

Roy stopped suddenly, staring at a patch of sand lying at the entrance to a lane. Tyre-marks were deeply impressed on the sand. Why had the car turned off the road here? The town was directly ahead, over the next rise.

For some time Roy stood staring down at the patch of sand. Had something happened to the youth—or the car? He bent and examined the tyre-marks more closely. He could see nothing wrong; so far as the marks showed. The car had been deliberately driven into the lane.

Keeping well away from the marks on the road, Roy followed into the lane. He knew enough of tracking to see that the car had stopped just before it reached the corner, and from there had proceeded at a more leisurely pace. What had Pat White meant to do by turning off the main road? Roy looked around him. The youth had not taken a short cut.

He climbed a rise and paused to survey the surrounding country. He was bearing south of Port Hacking and ahead the road bent decidedly eastwards. With a start Roy recognised that eventually it would run behind Hanson's house.

He walked on warily, watching the country on all sides. He came to the little thicket and paused; then entered. In the centre of the bush stood Hardy's motor-car.

What had happened to Pat White? Roy glanced around him nervously. So far as he could see there was no one around. But the bush was thick and might well be filled with Dr. Night's Chinese servants.

Bob Hardy had not received his message! A shiver of apprehension ran through Roy. Had Dr. Night discovered that he had traced him to Port Hacking? Had his spies reported to him Roy's arrival in the neighbourhood? Had he watched and seen Pat drive away in the direction of the city?

Roy turned on his heels and went to the road. There he hesitated. But first he should examine the car. So far as his untrained eyes could discover, there were no signs of struggle in the car. Roy examined the Interior minutely, then tried, the engine. It turned over perfectly.

Circling the car, he looked for footprints. Although the ground was sandy, he found none. How had Pat left the car? He returned to the lane and walked back to the main road where the car had stopped. Again he looked for footprints. He could not find any. Again he searched the road. He was certain someone had stopped Pat at this spot and under some pretext had entered the car. Then the youth had been overpowered or forced to turn the car up the lane to the thicket.

A strange streak on the ground caught his attention. He examined it more closely; puzzling over it for some time; then understood. There had been footprints in the sand and they had been smoothed out. Only in one spot had indications of the obliterator's work been left.

The newspaper-man turned resolutely towards the town. He would have to get to the telephone and ring up Hardy. Dr. Night knew that he had discovered his hiding-place, and was prepared. But did the Asian know that Hardy knew that Frederick Hanson was missing? He might assume that he, Roy, had come down to Port Hacking without taking anyone into his confidence. The attack on Pat White, the hiding of the motor-car in the thicket, pointed in that direction. He came to the long rise that hid the town from his sight. The surface was loose and he slackened pace slightly. Just before he reached the crest he stopped to regain breath.

A sense of unreality—of impending trouble came to him. Why had he stopped? To regain breath? That was nonsense. He was in perfect health. Almost daily he walked far steeper hills without discomfort.

A widespread tree grew close to the edge of the road. Almost without: conscious volition, Roy turned to it and threw himself down in the shade. A moment and he was fast asleep.

He awoke with a start. Heavy and drowsy, for he had slept soundly, he found the road and plodded on. He seemed to be walking for hours, with no result. At a turn of the road he looked up, puzzled.

Before him loomed the large greyness of Hanson's house. How had he come there? He had set out to walk to Port Hacking. He had rested—slept—on the way. Then he had retraced his steps!

He shrugged, laughing idly. He must have slept very soundly to have made a mistake in the direction he was travelling. He looked at the sun. It hung low in the western sky. A glance at his watch showed the time to be after six o'clock.

It was the hour of sunset and he had left the Mirror's offices early in the morning. He had come to find Dr. Night—and he had found him. But Dr. Night knew of his presence in the neighbourhood.

Hardy would be waiting at the Mirror's offices for word from him. He would wonder why Pat White had not returned with the car. Pat was now a prisoner in the Asian's house. He would have to get word to Hardy. He turned again in the direction of the town. Within a hundred yards the strange weariness again overcame him. Seeking a soft spot in the bush he threw himself down and immediately fell asleep.

The sun was high in the eastern sky when he awoke. He sat up, stiff and tired, straining himself, languidly. Through the bushes he could see the chimneys of Hanson's house. He stared at the windows of the top story idly. No smoke came from the chimneys: no signs of life showed at the windows.

Yet in that house, were crowded Dr. Night's Chinese servants. Perhaps there, also, were Pat White, Frederick Hanson and his family. They were prisoners of the Asian.

Roy stood up and shook himself. Close at hand a small creek wandered through the bush. He went to it and, after drinking long, bathed hands and face.

Refreshed, he took stock of his surroundings. The previous evening he had tried to get to Port Hacking, and had failed. Why?

He could answer his own question in two words—Dr. Night. He had now no doubt. He had not been tired when he had set out to walk to the town. The weariness had grown on him after he had found the car—when he had tried to get on to the town. He was a prisoner—a prisoner in open country; yet just as safely held as if he were confined between four walls.

Roy sat down on a bank by the wayside and laughed. A prisoner, was he? Well, gaolers were supposed to feed their prisoners, and he was hungry—very hungry.

Dr Night had watched him from the bush the previous day. Well, he should not have that trouble in the future. Shaking some of the creases out of his clothes, Roy climbed the wire fence bounding the Hanson estate, and walked towards the workshops where a number of Chinese appeared to be very busy.

CHAPTER XXVII

THE Chinese mechanics, gathered about a huge aeroplane in the space before the workshops, turned and gazed with mild surprise as Roy walked towards them. His heart was beating high, though he strolled on with an air of bored nonchalance. At the outskirts of the small crowd around the aeroplane he paused and examined the machine curiously.

As he had expected, only the frame of the machine had been completed. He could not see the interior of the cabin, for it was enclosed, but he was close enough to the wing to note that the spaces to contain the gravity plates were empty; there the wires swung loose.

A man came from the house followed by a couple of Chinese, heavily laden. At sight of Roy he stepped forward quickly. The journalist recognised Humberston.

"What the—" Suddenly he grinned. "Oh, it's you, is it? Thought you'd gone to town to telephone your pals?"

"Your—or should I say, Dr. Night's—invitation to remain was—irresistible," drawled Roy. "Seem to be busy, don't you?

"We'll be busier before long." The man spoke darkly. He turned to the laden Chinese and cursed them roundly. "Get up there with those plates. Oh, blast!" He glared around until he spotted a headman. "Say; you! What are you doing there? Tell these chaps what I said in their infernal lingo."

"His countrymen?" Humberston stared, then laughed. "Why, they're scum to him. He—Oh, damn you, making me laugh like that. You just say that to him and see what you'll get."

Roy nodded. Humberston but confirmed Hardy's theory that Dr. Night was a Central Asian. Allied to the Chinese he might be in blood and tradition, but he was of the older blood of Asia—descendant from the great tribes from the vast plains from whence, tradition tells, mankind sprung.

Humberston had turned to the workmen and was shouting rapid directions, interpreted by the headmen who scurried, about him like frightened rabbits. The newspaper man wondered why he was allowed to retain his freedom. Presently he noticed that a couple of hefty Chinese, armed with short, knobby sticks, were never far from him. Then hunger gnawed. He turned and walked to where the crook stood.

"Hungry? Well, a night in the bush ain't satisfying. Breakfast's over some while. Wait a mo' and we'll go up to the house and see what we can find. I can do with a bit myself."

Presently, assured that the work was proceeding correctly, the crook beckoned to Roy, and, followed by the two armed Chinese, led towards the house. A few steps and he waited for Roy to catch up to him.

"He cooked you nicely last night." The crook laughed "Lor', I laughed. And all in his room. He knew where you were, what you were doing, and what you thought. Played with you like he'd play with a kitten."

Roy had to laugh with the crook. The picture of Dr. Night, seated in his study, bewildering and baffling him while he wandered through the bush was painful, yet amusing.

"What of that young fellow I brought down here?" he asked suddenly. "He knows nothing."

Humberston laughed. "A nice lodging and three meals a day ain't too bad these days."

"What's the kid for, son? You know where the car is. I sat and listened to your thoughts while you wandered round it—looking for footprints, eh?" The wave of anger passed. "Don't try those games with the doctor. He's apt to get cross and—and then I'd rather face a mad dog. Biting's a little thing to what he'd do. Why—"

Roy looked about him. The room was empty except for a Chinaman busy at the stove. Humberston seated himself at the big table in the centre of the room, motioning the newspaper man to seat himself at his side.

"Chow—you," he bellowed at the Asiatic. "Wake up, there! Two of us, you yellow son of a dog!"

"Ain't it awful?" He barely changed his tone. "Only five people in over eighty speak a decent lingo and understand it. You can swear till you're black in the face and these darned Chinks only smile! What's a man to do?"

"Sure? Yes. What 'ud matter if they didn't. A Chow's made to be cursed and kicked, ain't he? Why, he's scarcely human. Big yellow apes!"

Humberston grunted and helped himself to the food the Chinaman placed on the table. He ate heartily, as if he had not fed previously that day. Roy finished some time before the crook and sat back in his chair, observant.

"Finished?" Humberston pushed his plate from him. "What are you going to do now?"

"Want to see him?" The crook laughed. "Well, he don't want to see you—or he'd have told me."

"Guess you recognise you're beaten. Sure. Knew the moment you walked out of the bush."

Roy thought a moment. If Dr. Night knew his movements so thoroughly and could read his thoughts, as he had done the previous night, what chance had he to succeed? He rose from his chair and went to the door by which they had entered.

"If I'm free to choose, we'll go outside," he laughed. "The open air for me every time."

"You're a good plucked 'un," he said, half to himself. "And you're going to see something, m'boy."

The crook did not answer. They strolled down to where the 'plane lay, the busy Chinese about it.

"What do you think of her?" Humberston laid his hand, proudly, on the undercarriage.

"Good!" Roy could not conceal his admiration for the graceful machine. "Almost ready to take the air isn't she?"

"Fishing for information?" Humberston laughed. "Well, why shouldn't you know? There's five more like this."

"As soon as the plates are made." The crook grinned. "That's why Dr. Night doesn't want you, yet. He's making them."

"With a couple of his Chink friends. Highly-educated ones. Calls 'em 'doctor' an' all that."

Dr. Night had six giant 'planes! Roy wished he had been more inquisitive when he had been talking to Hardy. How many 'planes was Sir Max building?

If Humberston was not lying, and Roy had no reason to believe he was, then Dr. Night would have a fleet in the air within a few hours—a despotic force, capable of imposing his will on all Australasia.

"Like to know, wouldn't you?" Humberston grinned. "I don't mind telling you one thing. Those works at Ashfield will have to close down now. You're here and Halliday's lost his memory. That leaves the secret with Dr. Night. Directly we're ready we go to Ashfield and blow the 'plane they have out of the skies. That's enough for you to know."

Halliday ill! sudden depression settled on Roy. That would hamper the work undertaken by Sir Max and Hardy. But would it? Had he not forestalled that move by Dr. Night. Frost, Doris, and Hardy knew the secret formula.

He would have to put that thought from him. He would have to forget it. He must school himself that only Halliday and himself knew the secret of the Whispering Death. Only by doing that could he save his friends from destruction.

Turning from the 'plane he sauntered leisurely towards the workshops. Humberston waited to give some direction to the headmen and then followed him.

Roy was amazed at the extent of the shops. He saws at once that recently they had been added to extensively.

Scattered about them were the parts of the other five 'planes. In one corner the second giant 'plane was being assembled.

He looked around for the small 'plane Dr. Night had stolen from Halliday. It was not in the workshops. He did not ask the crook. Sooner or later, if he continued to retain his freedom, he would discover it.

Almost afraid to think, he was building up a plan of escape, and the model 'plane bore a large part in his scheme. He idled around the place until he came to an office. Entering it he threw himself in a chair, as if weary.

"Now you're talking." Humberston turned to a cupboard and pulled open the door. He threw it shut, with a muttered exclamation, and turned to the yard.

"Lou!" he yelled. "Lou, you perishing dodderer. Where are you? I'll break your blithering neck When I get you. Cupboard empty, d'yer hear? Get some beer, can't you?"

No one appeared in answer to the crook's shout. Roy waited, hope rising in his heart.

Immediately Roy turned to the desk—and the telephone on it. He rang the exchange—for the machine was not automatic.

In an agony of impatience he waited. Would he be able to get a message through to the Mirror before the crook returned? Again he rang.

"Listen." Roy was straining his ears for the returning steps of the crook. "Listen! I'm a prisoner. Get this to the Mirror newspaper. Hardy right location. Act immediately. Danger."

CHAPTER XXVIII

BOB HARDY had expected Pat White to report back to the Mirror offices on the evening of the day he drove Roy to Port Hacking. When the cadet journalist did not appear the chief sub. was more annoyed than uneasy. He knew that Roy was on a dangerous mission. He should not have exposed the younger, inexperienced youth to peril.

Ruth was worried at Roy's complete disappearance. Doris had insisted on the Hallidays removing to her home at Pott's Point until the danger from Dr. Night had passed. Her experience of the Asian had taught her how dangerous he could be. The inventor was in peril. Until Dr. Night left the country, there was the menace that he would seek, tor kill all who knew the secret of the gravity plates.

Doris and Ruth had become great friends. The elder girl had penetrated her companion's secret. Together they would talk of their men in delightful inconsequence; Ruth gradually allowing herself to assume a sense of proprietorship over Roy.

Hardy and his wife consulted for a long time on the evening of the day Roy left for Port Hacking. The absence of news worried them greatly. The result of their discussion was that Hardy telephoned Sir Max, explaining the grounds for his uneasiness.

"I think Roy and Pat have been captured," the chief sub-editor answered promptly. "Dr. Night has an uncanny facility for guessing what his opponents are doing."

"Then they must be rescued." Hardy spoke emphatically. "Remember, Sir Max, Dr. Night holds the formula for making the gravity plates. He has his machines partly built, for he has had possession of the original Whispering Death for some time. His neglect to go after the formula immediately showed that he was working to a definite point. He wanted to have his 'planes ready to receive the gravity plates before he went after the formula."

"So." There was a long pause before Sir Max resumed. "You infer, Hardy, that Dr. Night will have his machines in the air shortly."

"That's right, Sir Max. If he has and he gets to know of our activities at Ashfield, then we're in great danger there. Again, if he gets his fleet in the air before we are ready, then 'good-bye' to Roy and Pat."

"Either that or he will carry them away on his scheme of conquest—into the interior of Asia."

"One machine is in the air, permanently, on guard. One more will be ready late today. Four others are awaiting the gravity plates. Eight machines are all but completed, as regards structure. Sixteen machines are in various stages of construction."

"Hard to tell, Sir Max. He got hold of the formula but a very few hours before Halliday gave it to me. His position depends on how far he advanced with the construction of the 'planes before he obtained the formula. Remember, he must have been building some time before we received our plans."

For the third time there was silence. "Can you get Lexton on the 'phone, Hardy—Lexton, the Ashfield manager?"

"Get him. Tell him that work on the first dozen 'planes must go on night and day with all possible hands he can get employed, until they are ready. That must be to-morrow evening at the latest."

"You have two 'planes ready? Yes. Get over Port Hacking to-morrow with those 'planes—for observation. Don't stir up a row and if that scoundrel has 'planes in the air, avoid a fight at all costs. Your job is to locate the two young men, if possible. Of course, keep your eyes open and try and get a line on what Dr. Night is up to. Goodnight."

Hardy was satisfied. He telephoned the manager of the Ashfield works, then went up to Doris' boudoir to tell her of his conversation with Sir Max. Ruth was with Doris, and, somewhat incautiously, he spoke rather freely before her. He noticed the girl fell silent and lost her colour.

THE NEXT morning Hardy left home early, for the Mirror offices, determined, later in the day, to go to Ashfield, and do all in his power to expedite the work on the 'planes. Just before midday he was surprised by Doris and Ruth walking into the reporters' room.

"Ruth's worried," Doris whispered when she found a chance to have a word with her husband privately.

"Of course. Didn't you guess that before? She's certain that Dr. Night has captured him. She wants to go out to Port Hacking and try and find some traces of him."

"But—that's madness:" the chief sub. entered in surprise "Why, if Dr. Night's there-"

"Dr. Night is there." The girl was positive. "Roy would not have stayed away unless he had found some clue—"

"If Dr. Night is out there, then he has found Roy," Hardy grimaced. "For Ruth to go out there is to give that scoundrel a lever to force her father to place himself in his hands."

Doris nodded. She knew the master-criminal would take every advantage given him.

The telephone bell rang sharply. Something in the tone of the bell brought all of them to attention. Hardy lifted the receiver and spoke the name of the newspaper. For a moment he listened his face blanching.

"Roy! Is that you, Roy!" He spoke in a strained whisper "Danger? In what way? Say, Roy." He jangled the hook angrily "Here, Exchange, you've cut me off! What number called me? Connect again, please. Important!"

"Roy?" Ruth had sped to the desk on the mention of the word. "Bob, was that Roy? Tell me. I must—I must know!"

"He said-" Hardy spoke slowly. "He said: 'I'm a prisoner. Get this to Mirror newspaper, Hardy right as to location. Act immediately. Danger!'"

"Ruth, dear! Don't worry!" Dons spoke cheerfully, although her face was white and the hand she lifted to her lips trembled.

"—you say the second 'plane is ready for flight. What of the third? Oh, you'll be able to have four machines in the air late this afternoon. Good!"

"Late this afternoon?" Ruth spoke sharply. "That is no good! Roy wants help now. Oh, you—you stupid men! Doris, come with me!'"

She turned, running to the door. Hardy made as if to stop her, but Doris stayed him. She picked up her gloves and bag.

"Now, dear. Where's your hat? My car is at the door and Ruth will be in it, waiting."

Hardy followed his wife, dazedly amazed. In Doris's car they found Ruth, impatiently awaiting them She slid from behind the wheel.

They drove to the great aeroplane works, recently acquired by Sir Max, in silence. When they came within sight of the sheds and flying ground Ruth's eyes sought and found the huge aeroplane overhead.

The great machine hung in the air over the sheds, about a thousand feet from the ground. At first glance it appeared to be no different from the ordinary machine, except that it hung motionless.

As the car drew nearer the works the occupants became aware of a queer whispering noise in the air—a slow, subtle sound that held a sinister, threatening note. It was as if someone was murmuring unintelligible threats over a long stretch of telephone line.

Ruth looked up at the machine, hope shining in her eyes. It was her father's mind-child. His brain had given it birth, and now she was to send it out—to find and rescue the man she loved. Yes, loved! She had no doubts now, although no spoken word had passed between her and Roy. She knew she loved him, just as certainly as she knew he loved her.

Hardy had jumped from the car almost before it stopped and ran into the office. In a few minutes he came out into the open, accompanied by a stout, short, thickset man, with a cheerful, ruddy clean-shaven face.

Almost as her foot reached the ground the 'plane above moved forward slowly and commenced to circle descending towards the ground in a steep spiral. It reached a spot above the flying ground and for a time-hung motionless; then fell directly to the ground—to halt ten feet up and then settle as gently as a bird.

Ruth gasped Now she could see the immense size of the machine. It was built of a strange white metal—a long, streamline cabin with a pilot's superstructure at the nose. The wings were very narrow, but of considerable length, in comparison with the body. On top the wings showed the white metal of the cabin, but underneath were of a pale gold; pale but luminous and rich.

"What do you think of her, girls?" Hardy turned to them, beaming with pride. "Beauty, isn't she? And Mr. Lexton says that they've tried her at five hundred miles an hour. Thinks she can nearly double that and stay in the air indefinitely. Oh, by the way, I forgot. Sorry, Doris. Mr. Lexton, our manager. My wife and Miss Halliday."

"What are you going to do with it?" Ruth pointed to the 'plane. Then, before Hardy could answer, she added: "Is she ready to go?'

"She's always ready, Miss Halliday." Lexton answered somewhat pompously. "She could go from here to to China-that is, if you didn't want to eat on the way."

"To China?" Ruth spoke quickly. She turned to her companions. "Come! Oh. come, quickly!"

CHAPTER XXIX

HARDY hesitated, but Doris caught the girl's infection. In a few minutes the preliminaries were settled. The aeroplane was to go to Port Hacking on a journey of discovery—and then return.

Ruth had demurred at the arrangement. She wanted to follow up any clue they might discover regarding Roy's whereabouts. She wanted freedom to follow after him and rescue him from the clutches of Dr. Night. She keenly desired to be near him, to touch him, to know that he was safe.

She mounted into the aeroplane, her hopes rising high. Yet, even with her thoughts engrossed with Roy, she could not but be aware of the terrible engine of destruction her father had evolved. The huge cabin looked as if it could contain an army, and beyond it were other cabins, kitchens, store-chambers, etc.

She sat at one of the windows, looking down at the ground, impatient for the journey to start. Suddenly the earth sank away, yet she felt no movement.

Again the strange, whispering hum sounded. She glanced along the underside of the huge wing coming from over her head and extending far from her. On it were dependent thousands of little plates of light gold colour. They were quivering—moving so fast that it was almost impossible for her eyes to follow them. Now she saw that the sounds came from their movement; yet, here, just beneath them, they sounded no louder than when they were a thousand feet up in' the sky.

She glanced downwards. The aeroplane was ascending rapidly—now over five hundred feet in the air, yet still directly above the flying ground. It gained another two hundred feet altitude, then commenced to move forward.

At first slowly, as if sliding down a long hill. The pace increased and the curve altered, until the machine's nose was pointing up again. Now the aeroplane factory had slid from sight—she could barely see it—far in the rear. The pace increased—a series of long ascents and descents. Ruth understood now. The machine-gained speed by attraction and repulsion from the earth.

A few more moments and Hardy touched her arm, pointing forward. Away on the horizon she could see a speck—an aeroplane. The machine in which she sat bounded up In the air until objects on the earth became so small that she could hardly decipher them.

They were rapidly approaching the coast. Again she looked for the 'plane Hardy had pointed out to her. It was so close that she could distinguish details on it. The machine carried no propeller. For a moment Ruth did not understand; then enlightenment came. She was looking at the original Whispering Death, the 'plane Dr. Night had built to her father's specifications—the 'plane the Asian had stolen from him.

"They can't do it!" Hardy laughed "We can go two feet to their one and jump a thousand feet higher into the air than they."

Both 'planes were mounting rapidly. The air grew so cold that the girl drew her wraps tightly around her. She looked out of the window again. Already the strange 'plane was almost beneath them Their 'plane had almost stopped its ascent.

"Checkmate!" Hardy laughed. "Sure, that's Hanson's house." He pointed down to the roof of an old sandstone building almost beneath them. "Why. what's that—in the yard?'"

A crowd of men, looking like minute ants, were clustered around some larger object on the ground. It suddenly became larger and plainer. Ruth looked around. Their pilot had succeeded in getting above Dr. Night's small 'plane, and had increased the power of repulsion, forcing it down towards the earth.

"That's the end of that!" Hardy chortled. "Good thing for them we're not armed. If we had been, they would never have reached the ground alive."

Again Ruth looked down. The ant-men surrounding the 'plane on the ground were scattering. The machine rapidly grew larger. She knew that it was ascending in meet them.

A bell close to where Hardy was seated rang. He took down the receiver and listened.

Their 'plane jumped quickly forward. Looking out of her window Ruth saw they were leaving the small 'plane rapidly in the rear. The bigger 'plane was now far from the ground and rising with extreme rapidity.

"Back to Ashfield." Hardy spoke shortly. "Hope Lexton has that other 'plane in the air. If not—" He went to the rear cabin.

They were travelling with extreme rapidity. Ruth noticed a mirror facing her, and under it a row of little knobs. Hardly knowing what was doing, she fingered the knobs. A few turns of the screws and a 'plane suddenly appeared on the glass.

It was the 'plane they had witnessed rising from the ground from Dr. Night's workshops. It was pursuing them, yet not gaining on them. Now she understood Hardy's anxiety. They were fleeing before Dr. Night!

But Dr. Night had Roy in his power. They were running away from Roy. She half-rose from her seat, then sank back wearily. A thought came, and she turned to the mirror again.

The rows of knobs under the mirror worked a periscope. A few moments and Ruth mastered the instrument. She swung the mirror right and left. At length another and smaller aeroplane came into the view.

Dr. Night had two aeroplanes in the air, the one he had stolen from the inventor and the newer, larger one. She turned from the mirror. Hardy had returned to his seat and was working a similar mirror to the one beside her.

"All right, old dear!" The chief sub. laughed as he caught her questioning glance. "We'll do them yet."

"Not going to chance anything." Hardy grinned. "We're unarmed. They may be armed or not. If they are, they can blew us out of the air. I was a damned fool to allow you girls to make this journey."

"Maybe we are."' The journalist laughed openly. "If they follow all the way they'll get the shock of their young lives. Lexton will have another 'plane over the factory, and I hope that will be armed. Watch out, ahead."

Ruth swung her mirror obediently. At once she picked up an aeroplane in the sky. A glance towards the ground and she saw they were approaching the Ashfield factory. A few moments and their pace slackened. They were gliding downwards and above them hung another silver aeroplane. Some distance in the' rear were their pursuers.

Immediately they alighted the door closed and the machine bounded up from the earth. Doris and Ruth clasped hands, looking up at the 'planes.

The four 'planes were now almost together, manoeuvring for position. In this, the second Ashfield 'plane was materially handicapped; It had to protect its rising friend, yet not allow the enemy to gain any advantage over it.

For some time the four 'planes circled and dodged. Ruth held her breath. She was witnessing air manoeuvres that no airman of her generation had thought possible. The machines were perfect and with complete command of the element in which they floated.

Circling and dipping, rolling and slipping, the four 'planes strove for the mastery. At length one 'plane dodged forward, then upwards, rising at a big angle.

The trick had taken the Ashfield 'planes by surprise. The enemy 'plane had gained great altitude on them. It dashed forward over the 'plane the girls knew, contained Hardy.

Something dropped from the tipper 'plane; something that glittered in the sunlight. A quick roll by the victim evaded the falling bomb. It came to earth in a field a short distance from the factory, shaking the earth and air with a tremendous explosion.

As if the dropping of the bomb had been a signal, the enemy 'planes turned and fled, towards the coast. The Ashfield planes hovered in the air for some minutes, not making any attempt at pursuit; then dropped to the ground. The girl raced forward amid a crowd of merchants. Doris seized Hardy in her arms, as he jumped from the machine.

"What can we do?" Ruth wrung her hands. "They have aeroplanes as big and as fast as ours. They can drop bombs on our machines and—"

"Cheer up, old dear." Hardy laughed. "Perhaps we'll have a surprise for them when we come in contact again. This time we were unarmed. Next time—Ruth, your father's a darned clever man."

CHAPTER XXX

ALTHOUGH Hardy had laughed, to Ruth and Doris, at the pursuit by Dr. Night's mystery 'planes, he was much disturbed at the incident. The Asian must have his preparations well advanced to dare drop a bomb so near Sydney and in open view of so many people.

What plans had Dr Night made? He had not completed his blackmailing schemes. The twenty financiers had professed not to have heard from him again Hardy did not believe this: nor did he believe Albert Wilson's statement to the reporters that the Asian had failed to keep his word and return the famous painting.

There lay a mystery. Wilson had valued the painting at a fabulous sum. He had paid Dr. Night's demand for ransom for the picture; yet he had not appeared distressed when it had not been returned to him. Britton Chambers had inferred that there was a mystery regarding the painting. Did the Asian know the solution of that mystery?

But above all Hardy was troubled at his inability to take the air with sufficient force to rout out the master criminal from his base at Port Hacking. He had four aeroplanes ready, but what force could Dr. Night oppose to them?

Half an hour after Dr. Night's aeroplanes had retired over the eastern horizon. Sir Max and Adam Halliday had come to the workshops. Sir Max listened to Hardy's account of the adventures, a frown gathering on his brow.

"That's serious. Hardy," he said when the journalist concluded. "Something will have to be done at once. You say we have four aeroplanes ready. What force can Dr. Night oppose to them?"

"We saw only two." Hardy spoke slowly. "Of course, we were alone and the machine they had on guard was the small model. If we had taken greater force—" he hesitated.

"Then—No, wait. Come with me!" He turned and entered the sheds. In the designers' room he found Halliday, handling a queerly-shaped piece of metal, something of the design of a small torpedo, but with a long length of wire attached to the rear end.

In terse sentences Sir Max explained the position to the inventor. Halliday listened In silence.

"So there is the position," Sir Max concluded. "You know the powers of your Invention better than we do. Can we challenge Dr. Night in the air with the four machines we have ready?"

"And they are more speedy and powerful than those Dr. Night has," Halliday spoke carefully. "The plans that man has are of the small experimental 'plane he built under my direction. In the plans I gave you, for the larger machines, I have made several important improvements. Then, there is this."

He held up the strangely-shaped torpedo he had held on his lap. They looked at it curiously. Halliday smiled and nodded to Lexton.

The manager went to a metal box on the bench and threw over a switch. Immediately the strange, gruesome, whispering noise of the 'planes filled the room. The torpedo appeared to quiver with life For some seconds it lay inert, yet vividly alive, then rose in the air.

The three men watched Lexton in silence. Before him, on the top of the box, was a row of buttons. His fingers played over them lightly. As he pressed each knob the torpedo swerved, dived or rose in the air.

A model of an aeroplane, about three feet long, hung from the roof of the shed. As if obedient to the Inventor's voice, the torpedo altered its course and sped under the aeroplane. For a moment it stayed, then darted up.

The torpedo hardly appeared to touch the aeroplane, but the strange, whispering increased in volume. Then the torpedo dropped to within a few feet of the ground. Almost immediately the aeroplane appeared to dissolve into air. A slight shower of dust sank to the floor.

"The complement of my aeroplane, Sir Max." A fanatical light of triumph shone in Halliday's eyes. "The torpedo works on the same principle as the aeroplanes. Mr. Hardy, do you think you would have to fly before Dr. Night's aeroplanes if you had this with you?"

The journalist shook his head. His lips had paled as he witnessed the disintegration of the aeroplane, yet his eyes shone brightly.

"Three days." Hardy shook his head. "Too long. If we are to act we must start at once. Sir Max, why should we not act? Two of these torpedoes will give us absolute security."

"Dr. Night will not wait." Hardy spoke rapidly. "Directly he has his 'planes in the air he will act."

"I have tried to guess." The newspaper-man frowned. "Either he will make direct for his own country or come here and smash up these works. He may hold Sydney to ransom for the balance of the demands, he made on the 'twenty."

"I propose to provision the ships we have for a long voyage. Go to Port Hacking and rout out Dr. Night. I don't expect to find him there, however. After his demonstration to-day, he will move rapidly."

"He will go to China." Hardy spoke with sudden inspiration. "Yes, he will not wait now that he knows that we have tracked him down. I know the man. The main thought in his mind is to re-establish the throne of his ancestors. He will go direct to Central Asia."

"What else can we do?" the newspaperman gestured. "We dare not allow him to roam the world in command of that fleet of aeroplanes."

"You propose to follow him and when you catch up to him destroy him and his aeroplanes?"

"Then I am coming, too." Sir Max spoke decisively. "No, Hardy, it is no good protesting. I have made up my mind."

Hardy hesitated, then nodded. The inventor had a right to be included in the expedition, in spite of his disabilities.

"And Doris and I are coming." Ruth spoke quickly. "No, Mr. Hardy, I must go. Roy is—is—"

Sir Max and Hardy expostulated with the girls. To their surprise they found that the inventor joined with the girls! He claimed that the aeroplanes were entirely safe, even if attacked by Dr. Night; that the journey would be little more than a new adventure, with hardly any risk.

An hour later the details were settled. Hardy and Halliday went into the workshops to oversee the making ready of the planes. Doris and Ruth went home to pack for themselves and the men. Sir Max undertook the provisioning of the expedition and spent a busy hour at the telephone.

It was at the hour of sunrise when the party reassembled at the Ashfield, workshops again. Doris and Ruth were the first to arrive, their car filled with luggage. Then closely followed Sir Max. They found the flying field occupied by the great 'planes, each one surrounded by stacks of provisions and necessities for the journey.

In silence, the girls watched the completion of the preparations for the flight. At last, all was ready and Hardy, appointed commander of the expedition, turned to them.

"Doris, Ruth! Won't you stay at home, please," he pleaded. "This affair may be horribly dangerous."

"Ruth must go, because of—Roy, and you know, dear, that Roy at present, is far less to Ruth than you are to me."

With a sudden, hard grasp of the hand, she passed him and followed Ruth into the cabin of the flagship of the little squadron. Sir Max followed her, looking more like a boy indulging in a forbidden spree than a responsible business man With a shrug, and a laugh, Hardy followed. As he entered the door, he turned and fastened it.

For some moments there was silence, then on the still morning air came the gruesome whispering of the gravity plates. The sounds grew in intensity and then the earth suddenly dropped from view. Flying in wedge formation the fleet made for Port Hacking. In a few minutes they were over the town and hovered over Hanson's workshops The place appeared to be deserted.

"Where have they gone to?" Doris bent over Bob, seated before the wireless control board.

Hardy nodded. He whispered a few words into the receiver and the huge machine dipped to the earth, leaving her companions hovering high in the sky.

As the 'plane touched earth, a man stepped out from the house and looked up to the sky.

CHAPTER XXXI

HARDY jumped from the machine as it touched the earth. The man advanced slowly, hesitatingly. A tall, fair man, with keen grey eyes, he blinked uncertainly in the sunlight, as if he had long lived in the dark. The journalist gazed at him a moment, puzzled. He thought he should know this man; his face and form were familiar, but—Then he smiled. Mentally, he had clothed the man in a flier's uniform—and remembered.

"Robert Hardy, of the Mirror." The newspaper man laughed. "Now in command of the Australian fleet of Halliday gravity 'planes."

"You mean Dr. Night." Hardy turned co his companions, who had alighted and walked to where he stood with Hanson "Doris, Ruth. Let me introduce Captain Hanson. V.C., war-ace and noted airman Sir Max. I don't believe you require introduction. Captain Hanson sat next to you at the Commemoration luncheon last year. Hanson, my wife and Miss Halliday, the latter the daughter of the inventor of these aeroplanes."

The airman mechanically acknowledged the introductions. His eyes passed from the huge machine resting in his ground to the squadron hung motionless in the air. He was puzzled, bewildered. These machines, without engines and propellers; that came to rest on the ground without wheels and under-carriages; that hung motionless in the air; were strange, unnatural to him. With a muttered word of apology he broke from the group, intent on satisfying his immediate curiosity.

Sir Max and Hardy exchanged glances and laughed. At a low word from the journalist the millionaire led the girls to the house to meet Mrs. Hanson and her children. Hardy returned to the aeroplane. There he found that Hanson and Halliday had become acquainted, and were deep in technicalities regarding the powers and achievements of the gravity 'planes.

Nearly an hour later the party gathered in the old-fashioned living-room of the Hanson's house, to listen to the airman's story of their capture by Dr. Night.

"It was all over in a few seconds," he said quickly. "The house swarmed with Chinese. We were herded into this room and a slight, grey man, wearing a skullcap, entered. He was very polite. Apologised for inconveniencing us, but said he had to have the use of my workshops for a few days. I protested, but was unable to move him."

"We were not badly treated. A suite of rooms on the first floor were set apart for our use. Our meals were brought to us. The only thing denied us was our liberty."

"I believe Dr. Night captured two young men that he accused of spying on his work," Hanson answered immediately. "I never saw them, but one of the Chinese, who spoke a little English, told me that he had others to attend to. He pointed at the ceiling as he spoke."

The airman turned to Hardy. "I cannot understand one thing. How comes. Dr. Night to possess machines of the same pattern as yours, if you and he are at enmity?"

Hardy had to recount the story of Halliday and his invention. Hanson listened in silence. When the journalist concluded his narrative the airman nodded.

"You say these machines are an improvement on those possessed, by Dr. Night?" he questioned the inventor.

"Out to sea." The airman pointed due east. Then, noticing the journalist's chagrin. "But he cave me a hint as to his destination."

"He thanked me for my hospitality." A slight smile flecked the airman's lips. Then he added: "I go to my country for the work that lies in my hands. I shall come again, remember!"

"He will come again!" Hardy muttered the words. "He said that before, and he has twice fulfilled his promise. This time—"

An exclamation from Sir Max drew all eyes to him. From a dark corner of the room he had drawn a roll of canvas, partly bound in brown paper. As he unrolled it an envelope dropped to the floor. Hardy seized it; then exclaimed at sight of the picture:

Sir Max nodded. He knew the painting well. It was the Murillo that Dr. Night had stolen from Wilson; the painting that the financier had ransomed for fifty thousand pounds.

"What does the letter say, Hardy?" the millionaire asked quietly, not lifting his eyes from the canvas.

The Journalist tore open the envelope and took out a slip of paper. He read the few words on it aloud:

Dear Mr. Hardy,

Will you please return the accompanying counterfeit picture to Mr. Albert Wilson. It may please him to replace It. In the hall of his home. I was Interested to obtain the loan of It—to try and discover why Its owner prized it so highly.

I have solved the mystery. Mr. Wilson loves his money—he loves to be considered an art connoisseur. In an endeavour to reconcile greed and vanity he sold the genuine painting after he had had it very capably copied.

I have punished his greed. Will the exposure your newspaper will undoubtedly make curb his Inordinate vanity?

Dr. Night.

"And Fate, or Dr. Night, is right," exclaimed the newspaper man. "Dr. Night and I will meet again, and soon. This man must be captured or destroyed."

"To follow him, if it be to the world's end." There was passion in the man's voice.

"I'm with you!"' Hanson Jumped to his feet and seized Hardy's hand. He turned to Halliday. "I'm at your service, sir, if you care to trust me with the command of one of your aeroplanes."

"Robert Hardy is in supreme command of the fleet." There was assent to the airman's impulsive request in Halliday's voice.

Hardy laughed. "If the command of the aeroplane will satisfy you, captain, it is yours."

The group turned quickly. The door had opened without anyone being aware of it. On the threshold stood Inspector Frost.

"So I have not been forgotten." The Inspector smiled quizzically. "At one moment I had a suspicion you intended to side-track me, Robert Hardy."

"I most certainly am coming." Frost glanced down at the suitcase at his feet. "You forget that I hold a warrant for Dr. Night's arrest."

"China, or Russia." Frost smiled. "Is that where our friend is heading? Well, well! One never knows."

"Where an Australian warrant will run." A twinkle of amusement lit the Inspector's keen eyes. "There was a certain European Emperor who didn't think one was worth a cuss—and he nearly got it nailed to the gates of Berlin."

"Got a license for that thing out there?" The Inspector pointed out of the window at the resting aeroplane. "Dangerous weapon that!"

"Then, the sooner we get a start, the better." Frost spoke imperturbably. "Dr. Night won't wait for us—and I don't know that I want him to."

"Not 'Inspector' for this Journey, Sir Max." Frost's hand opened for a fraction of a second, to show a strangely shaped badge on his palm. "I held the King's Commission during the War. On this journey I go, not as Inspector Frost of the New South Wales Criminal Investigation Branch of the Police Department, but as Captain Frost, of His Britannic Majesty's Secret Service. My orders are—and they have been confirmed by every civilised nation in the world—that the man known as Dr. Night is no longer to trouble the peace of the world—at any cost."

CHAPTER XXXII

THE great aeroplane throbbed to the low, sinister whisperings of the gravity plates; then gently lifted from the earth. Faster and faster she rose, springing up to join her sister 'planes, hanging motionless in the air above. She came to her place at the point of the wedge and for a long moment hung motionless.

In the big cabin Doris and Ruth clasped hands, watching intently Bob Hardy, who sat at the wireless control board. Through the glass door, opening to the nose of the 'plane, they could see Captain Hanson's back, as he sat at the control board, flanked on either hand by the steersman and his second in command.

They had started on their dual quest—In search of Roy and Pat, and to take or destroy the greatest master-criminal the world had ever known. Before them and seas—lands dimly known to white lay thousands of miles over tropical lands men. They were going into the heart of Asia, there to find a forgotten city and a forgotten race.

Through the air before them flashed Dr. Night, intent on making the land of his forefathers as quickly as possible. There he sought to re-establish a mighty empire, so long fallen that it had been swept from the records of the world.

Robert Hardy believed that Dr. Night designed to recreate that forgotten empire—that kingdom swept away in one of those cataclysms that periodically sweep the nomadic tribes of Central Asia—tribes that even, at the present day, owe but very loose allegiance to the empires that claim sovereignty over their lands.

And to accomplish his purpose. Dr. Night would have again to sweep the world with the horrors of war. He would have to plunge two mighty empires in a sea of blood. To him might, gather a few of the tribes in whose traditions still lingered a traditional loyalty to a long-lost empire. He might gather those nomads to the city of his fathers, seat himself on the throne his family had occupied, consolidate his rule; and then—

With the immense power of the gravity 'planes in his hands, there could be no doubt but that the Asian would embark on a career of conquest. He would win his ancient empire and beat back, with the greatest ease, the empires of Russia and China, who would seek to stay him.. He would extend his lands and authority. Would he then be satisfied with the empire his forefathers had ruled? He had seen modern cities and countries: he had known their wealth.

Would he seek to conquer far from his traditional borders? With the mighty, irresistible weapon of war he held, would he be satisfied with less than world dominion?

Dr. Night held the keys of war and peace in his hands. Against him were only the six aeroplanes Sir Max had built to test Adam Halliday's invention. More, these aeroplanes were being used as instruments of order and revenge—and in international law they had no standing. They were pirates!

Hardy smiled as the thoughts flashed through his mind. He glanced into the periscopic mirror, focussing the Australian flag at the stern of his flagship. More logical would it have been to hoist the skull and cross-bones—whatever his intentions.

The long minutes of the journey lengthened to hours—and they had passed far from the shores of Australia. The hours lengthened to days and still they sped on, their mark the heart or Asia.

The door of the forecabin opened and Hanson entered. With a curt nod he dropped into, a lounge chair by Hardy's side and rolled a cigarette.

"Some 'plane, this!" he grunted when the cigarette was drawing to his satisfaction. "Interesting to try a novice hand on her."

"Isn't it?" The aviator grinned. "I've tried a sail-plane and a glider, but I never heard of a 'plane that shoots through the air like a rocket. Say, boy! Where'd we hit if I pulled that control dead over and held it?"

"A child could understand this machine in five minutes." The man heaved a deep sigh. "Any child of five could handle this machine. No engines, no propeller! No watching oil and petrol gauges. No listening for knocks in the engine; watching for broken feed pipes, with one eye ever on Mother earth looking for probable landing places. Lor', what's aviation coming to, with men like Halliday taking a hand?"

"Sundown." Hanson spoke. "And there's Java right ahead. To think of it! And but yesterday we thought ourselves good if we flew from Sydney to Wyndham in a couple of days. Are we going down at nights? If so, well, it's dark down there, y'know."

"What for?" Hardy raised his eyebrows. "Oh, you haven't got over the petrol complex yet. No, we don't touch soil this side of Semarechensk."

"How about reliefs?" Hanson spoke quickly, as he gained his feet. "Shall I relieve Andrews while he feeds?"

Hardy grinned. He spoke a few words in the wireless, and immediately the 'planes drifted to rest, still in wedge formation.

The meal was a strange one. It was the first time they had eaten in the aeroplane. Hanson watched out of the window beside him nervously. He could not understand leaving the machines uncontrolled.

"What happens when two logs drift together on a placidly flowing stream?" It was Halliday who answered. "A few bumps, that's all."

Hardy glanced at his companions. Not one word had been spoken of their quest and its probable outcome. There was a tacit understanding that the subject was not to be mentioned until their journey was nearing completion. A slight smile shone in every pair of eyes that met his.

He knew the query that dwelt insistently in his own mind. What would happen when they reached the City of the Gods to which Dr. Night was leading them? Would they find the Asian there; the city defended from the air by the 'planes Dr. Night had built at Port Hacking? Would the Asian attack them, or remain on the defensive?

Or had Dr. Night some deep-laid scheme into which his apparent flight was drawing them? A frown puckered the newspaper man's brow. Had he been unwise to give in to the pleadings of his wife and Ruth, allowing them to come on this wild adventure? What would be the result of an air-fight between the two fleets? Would their vast speed and mobility result in the annihilation of all the aeroplanes engaged?

He rose suddenly from his seat and strode back to the wireless control board. For some minutes he sat in deep thought, then went to the table on which the charts were spread. For a long time he sat working set after set of figures. He looked up to see Hanson by his side:

"Carry on, man," he approved. "Three quarters speed would bring us to the Land of the Seven Rivers by sunrise."

Again Hardy checked his figures; then turned to the mike. For a few minutes he gave bearings and speeds, then, in a louder voice, gave the order to proceed.

Night fell. The soft glow of the hidden lights illuminated the cabin of the airship. After much urging Sir Max and Hardy managed to persuade the girls to go to their cabins. Hanson went forward to take his turn at the controls. Sir Max sat by the wireless control, silently smoking. The newspaper man lounged back in his chair, the earphones clasped to his head.

For hours through the silent night the two men sat in silence, too tensed to think of bed, intent only on the new day and what it would bring in its train. Suddenly Hardy stiffened.

He touched Sir Max sharply, pointing to a row of figures on the desk before him. The millionaire went to the chart table, to return a moment later and nod Hardy indicated the window. Away to the east shone the first rays of the rising sun.

"Someone's calling the Doris." The newspaper man spoke suddenly. Then into the instrument: "Doris speaking!"

"Welcome to Semarechensk." The cool suave voice Hardy knew so well spoke out of space. "He whom you know as Dr. Night bids you welcome to the land of his ancestors."

CHAPTER XXXIII

HARDY turned to Sir Max, a slow grin growing on his lips. A touch of his fingers threw over the wireless control.

Without waiting for a reply he strode to the window and looked out on the dawn. The earth beneath was still shrouded by the ends of night. Then, suddenly, the sun shot above the horizon, bathing the earth with wondrous beauty.

Behind the aeroplane lay the towering heights of the Barochoro Mountains, clad in serried ranks of towering timber, the leaves glistening green in the early morning rays. Almost directly ahead was a vast inland sea. Hardy had not to refer to the charts to know that this was Lake Balkash. Immediately beneath the 'planes was a bewildering network of rivers and creeks.

"How beautiful!" The newspaper man turned to find Ruth by his side. "Bob, are we there?"

Hardy nodded. "There flow the seven rivers—Semarechensk—the country Dr. Night claims as his own. Yes, we're there. Ruth, and—"

"Don't worry, Ruth. Dr. Night does not kill prisoners. Roy is safe, even is his freedom is curtailed."

"An hour ago I received a message from Dr. Night, bidding us welcome to his country."

"Look!" Hardy pointed before them. To their right lay a long chain mountains. The aeroplanes were following the course of a mighty river. On the left bank of the river, on a rising piece of ground close to the lakes, rose the white walls of a large city.

"Dr. Night's ancestral home." A faraway look come into Hardy's eyes. Again he was in the underground cavern with the painted walls outside Sydney.

Again, in his vision he was wandering over a deserted land towards a city encircled with pure white walls. He passed the wide-flung gates and walked the silent streets, set with long deserted houses. Again he came to the vast central square before the marble temple and stopped before the high-set throne. Again he gazed up at the mysterious Asian, sitting majestic in the seat of his fathers. He saw the Green Pearl bound to the furrowed forehead. Again he heard the cold, ringing voice of the supreme criminal.

No, not criminal. He could not vision Dr. Night as a criminal. The man was mad, beset with beliefs that had long since passed from this earth. He was obsessed—a man with an idea impossible to realise whatever the powers he had inherited from his long-forgotten race.

Was that vision, dreamed in the tar southern city of Sydney, to materialise now? He recognised the gates of the city he had dreamed of. From the air he strained his eyes to follow the line of streets he had dream-walked; to search out the high throne; to see the small figure seated there, clad in wondrous royal robes.

An urge he could not understand bade him halt his fleet and descend to the earth. Again he looked towards the city, now looming large. He strode to the control board and gave the order to stop.

The 'planes drifted forward, slowing until they hung high in the air, motionless, some five miles from the city walls. Through his glasses Hardy searched the skies. He could not see Dr. Night's aeroplanes. Where had the man hidden them?

Had he concealed them in the city? That was hardly possible. Dr. Night knew that Hardy and his friends were following fast on his heels. But a few hours before he had let him know that he was approaching the land he claimed to reign over.

What plans had the Asian made? Hardy had expected that he would have been met by Dr. Night's air fleet at the frontiers of Semarechensk and warned not to proceed further. He might have had to fight—to force a way through the barring fleet. Instead, he had found the frontier open; he had been met with words of welcome.

He studied the contours of the city and the surrounding country intently. He could see no signs of life, save for the few animals that lingered on the rivers' banks.

What should he do? Logically, he ought to advance with all speed and occupy the air over the city. If the air fleet lay within the white walls then he could destroy them in detail, as they rose into the air.

But back of his mind was a strange fear of the mysterious Asian and the almost superhuman powers he possessed. Dr Night did not react to the ideas of ordinary men. He was a law unto himself. A man, yet with powers far beyond those known to be possessed by other men.

"Why the stop, Bob?" Hardy turned, to meet the inquiring gaze of Inspector Frost.

"And why not look before I leap?" countered the newspaper man. "I am remembering that I am responsible for quite a few lives in this fleet."

"Mrs. Hardy and Miss Halliday," interpreted the police officer. "Wrong to bring them, y'know."

Hardy grimaced. A shrug and he turned to re-survey the city. For some minutes there was silence, then the newspaper man continued:

"Look!" The newspaper man pointed to a column of smoke that rose from a tall tower in the heart of the city.

The smoke rose straight into the still morning air until it towered above the altitude at which the 'planes floated. It mushroomed, spreading out until it covered the city with a black pall.

For more than a quarter of an hour the black column of smoke continued to rise, thickening and darkening the cloud. At length it ceased to pour from the tower.

The thick black cloud of smoke hung motionless over the city for about five minutes. Then, where the rising smoke had impinged on the cloud a slow whirling motion commenced, stirring the cloud as if to boiling point.

From the cloud came vivid streaks of lightning, but no sounds of thunder—nor was the cloud rent by the lightning. The storm boiled and swirled, but always the cloud confined its borders within the city walls.

With the swiftness of a flash of lightning the cloud disappeared. Again the bright northern sun shone down on a city of exceeding whiteness.

Frost pointed, in almost awe, to where the cloud had hung. There, in the brilliant sunlight, floated six aeroplanes, sister ships to those Hardy commanded.

"Keen, very keen!" The newspaper man turned to find Sir Max standing behind him. "Got his 'planes in the air under cover of the smoke cloud."

"And the lightning, Sir Max." There was a note of sarcasm in the Inspector's voice.

"Anyway, I'm glad I didn't take our 'planes into that cloud." Hardy saw his companions' nerves were on edge.

For some moments Hardy did not reply. His gaze was fixed on one of the gates of the city.

From the gate issued a stream of white-clad men mounted on white ponies. Outside the walls they formed, with military precision, into regiments and trotted out into the country, making for the angle of the river over which the pursuit 'planes hung. Two of the 'planes hovering over the city detached themselves from their companions and escorted the horsemen.

The crew of the "Doris" watched the advancing regiments in silence. Presently Hardy felt a touch on his arm. He turned. Doris and Ruth were standing beside him.

"What does it mean? A fight?" Doris's fingers pressed on her husband's arm, heavily.

"I don't know." The newspaper man frowned. He turned and with his arm around his wife's waist went to the control board.

A few simple instructions and the Doris floated down to meet the advancing horsemen. The remaining 'planes closed their formation, still maintaining their altitude.

One of the 'planes escorting the horsemen sped forward and downward. Now Hardy saw that from a pole set over the pilot's cabin floated a white flag.

CHAPTER XXXIV

HARDY walked into the forecabin of the aeroplane and touched Hanson on the shoulder.

The aviator rose and followed Hardy into the main cabin. The newspaperman halted just within the door, slid it shut.

Hardy pointed to the horsemen, grouped around a clear space of ground, over which their 'plane hovered.

"Don't argue, old man. It's just that or fight, and you've seen something this morning of Dr. Night's diabolical powers."

"It's up to us two." Hardy lowered his voice. "Dr. Night has to be stopped or—" he shrugged. "—well, we've been over all that before."

"Take the Doris into the air. I can't have the girls in danger. Send another 'plane down here and—Oh, damn it! You know what to do if I don't come back."

The newspaper man turned and caught the Inspector's eyes. He beckoned slightly. Frost nodded, and as the aeroplane settled gently on the ground strolled over and joined the two men.

"There's our escort." The journalist pointed to the horsemen. "I'm going with you to visit Dr. Night."

"I've got to slip away." The journalist grimaced. "Hanson will have to manage that. Ready?"

Without waiting for a reply he slid open the door and stepped down to the ground. Frost followed him closely. One of the horsemen rode quickly forward and a few yards from Hardy dismounted.

"I bid you welcome, Robert Hardy," he said in clear English. "The Master awaits you."

"Thomas Humberston." He whistled "Humph! Know I hold a warrant for your arrest. Thomas Humberston?"

"Australian warrants don't hold in this country, Inspector," the man laughed mockingly. "Here, Dr. Night is master and—" He finished with an expressive shrug.

The Inspector frowned, but did not reply. He followed Hardy to where a couple of led horses stood, and mounted.

"Bob! Bob!" A sudden flurry amongst the surrounding horsemen and Doris broke through. "Where are you going?"

"To visit Dr. Night." Hardy flushed, uncomfortably. "Doris, go back to the aeroplane, please."

"I am going with you." The girl turned to Humberston, whom she recognised as the leader of the party. "A horse, please."

"And one for me." Ruth pressed her way through the throng. "No. Bob! I've got to go to Roy."

The Australian crook smiled sardonically and motioned to a couple of the horsemen. They dismounted and helped the girls to the saddles. Hardy shrugged, helplessly. Humberston mounted and rode to the head of the party.

In silence they rode to the gates of the city. Hardy was worried. He believed that if he and Frost had been alone they could have extricated themselves from any difficulty they got into. But the girls being with them complicated matters enormously.

At the city gates Humberston motioned Hardy and his companions to dismount. Within the walls the horsemen turned sharply to the left and, skirting the walls, disappeared into a maze of narrow streets.

The crook motioned Hardy to lead on, up the main street of the city, beckoning Frost and the girls to follow him. For a moment the newspaper man hesitated, then stepped forward boldly.

He knew the way. In his mind recurred vividly the streets he had paced in his dream six years before. He recognised the heavily built stone houses he was passing, with their shuttered windows; the utter lack of people in the streets and houses.

The street widened and the houses became more imposing. Yet still he saw no one except the members of his party, even Humberston had disappeared. As in his trance, the city was deserted.

He led into the big central square before the magnificent Temple of the Gods. He halted, abruptly, facing the huge white throne erected in the centre of the square. On the raised seat sat Dr. Night clad in magnificent royal robes, and bound to his forehead was the Green Pearl. In wonderment he looked around him. Not a soul was in sight.

"Welcome, Robert Hardy!" The cold, suave voice rang through the empty space. "What seek ye?"

"The restoration of what you stole." The words came involuntarily to Hardy's lips. "Give me the 'planes you built from the plans you stole from Adam Halliday; give me the two young men you hold prisoners, and I and those with me will depart in peace."

"Then the aeroplanes that I have brought with me will take the aeroplanes you stole and will not leave one stone of this city standing upon another."

"You held me before and yet I conquered." Some inner force brought the words to Hardy's lips.

A frown passed on the Asian's brow. For a moment he was silent, thinking deeply; then pointed into the air.

"There float my aeroplanes. You saw them spring into the air. They are yours to take."

Again the Asian was silent. For long minutes they waited. Then Dr. Night rose to his feet and turned to face the temple. He extended his hands, palms upwards. A moment, and his fingers bent in a slow beckoning, partly clutching, gesture.

The doors of the great temple swung slowly open and on the threshold stood Roy and Pat. Again the doctor motioned, and they came forward on to the great terrace before the building. There they halted.

"Roy!" In a moment Ruth was running across the square and up the broad steps to the terrace. On the last step she hesitated. Hardy could see that she strove to go forward, but that some Invisible power held her back. She stretched out her arms to her lover, crying aloud his name. Neither Roy nor Pat took notice of her.

"There are the young men." Dr. Night spoke slowly as he turned and faced Hardy. "They are unbound."

"The shedder of blood shall die in blood!" The sonorous words rolled through the empty space. "Man of blood, look!"

The little group looked around them in amazement. Where before they had been alone in the square with Dr. Night, now the place was filled with white-clad, figures. They had not seen them come: there had been no movement In the square or in the surrounding buildings. The people had, apparently, been incarnated from the air.

Again the trumpet blared. Every head bowed to the slight figure enthroned high above their heads. In the crowd a movement formed, those nearest the throne Dressing back until a broad lane opened from one side of the square to the other. Alone in the lane stood Robert Hardy and his companions.

From the east side of the square came the trampling of hoofs. Into view rode slowly the troops of white-clad horsemen. With lances held high they paced forward until they lined from side to side of the square, before the white throne.

Some thought caused Hardy to look upwards. Again the thick black cloud was rising from the temple tower, enveloping and hiding the circling aeroplanes. As the cloud formed over the city the 'planes rose above it.

Something was tugging at Bob Hardy's pocket. He looked down. Doris was pulling at the slender chain fastened to his coat. His hand went up to it, but she frowned and shook her head.

At length the chain gave and she held in her hand a silver whistle. Placing it to her lips Doris blew a loud, shrill blast. Immediately the people in the square, the serried ranks of horsemen, vanished, leaving only Ruth and the two young men standing on the temple terrace.

As if the sound of the whistle had been a signal Roy sprang forward and clasped the girl in his arms.

CHAPTER XXXV

HARDY looked up at the sky. The steady stream of smoke that had poured from the temple tower had disappeared. The cloud that hung above the city was drifting out over the open country. High above the city hung Dr. Night's squadron of aeroplanes.

His face paled and he glanced anxiously at Doris. She was holding his arm, staring triumphantly at the gauzy figure on the high white throne.

"Quick, Bob! Speak!" she whispered. "Don't you understand! You saw—we saw only what he wanted us to see."

Dr. Night was disturbed. He had half-risen from his throne, one hand extended towards the little group in the square.

"A bluff! Mesmerism!" Frost darted forward up the steps of the throne. "Dr. Night—whoever you are—I arrest you."

The extended hand slowly lowered until it pointed direct at the inspector—pointing at him between the eyes. The police officer hesitated, staggered, then fell, and rolled down the broad white steps until he lay at Hardy's feet.

"Peace, I command!" The slight figure standing before the huge throne spoke hesitatingly. "Peace, or from the skies will rain down destruction upon you."

"Ruth! Roy! Pat!" Again Doris raised the whistle to her lips and blew a loud call. "Here! Quick!"

Her words aroused the little group on the temple terrace. Ruth seized her lover's hand and ran down the steps and across the square to Doris's side.

But Hardy's lips were tied. He stared vacantly up at the figure on the throne. In sudden desperation the girl placed her hands over his eyes, shaking him roughly.

As though awakened from a trance Hardy stepped back, nearly falling. He glanced upwards into the sky. A sudden, triumphant look came into his eyes. He raised his arm, pointing upwards.

"You have refused peace, declaring for war!" His words rang clearly through the space. "Now, look!"

From the south, travelling at incredible speed darted Halliday's squadron of aeroplanes. They swept over and around the city in a wide, sweeping circle; then rose high in the air towering above Dr. Night's gravity 'planes.

Again from the south darted a single 'plane. It swept low over the great square, dropping until it hung motionless but a hundred feet above the man seated on the high throne. Gradually it descended until it was only a few feet from the ground.

High in the air the two fleets were manoeuvring for position. Halliday's aeroplanes had obtained the upper position, and were intent on keeping the advantage. The Asians' ships were twisting and turning, striving to mount above their opponents.

The Doris almost collided with one of Dr. Night's 'planes, the collision only being avoided by the Doris suddenly rebounding into the air. The 'plane with which the Doris had almost collided shivered and rocked, then fell like a stone into the city. Through the gruesome whisperings of the gravity plates the crash rang loudly.

"Dropped almost on her opponent and then turned on the full force of her gravity plates. Understand, dear? She pushed at the earth with all her force, and as that 'plane happened to be between her and the earth it got the full force of her power. Smashed and drove it down. Halliday did that. Hanson wouldn't have thought of it!"

The Doris was now under the enemy planes. She rose towards them slowly, dodging and slipping as they tried to bomb her. Suddenly she fell again and, where she had been, floated a small speck of metal on which the sunlight glistened brightly.

The metal torpedo hung motionless for some seconds, then suddenly darted towards one of the aeroplanes. The machine darted aside, as if seeking to escape, but the torpedo, like a hawk in pursuit, sped after it.

For seconds that seemed like hours the 'plane sought to escape from its tiny pursuer, but in vain. Twist, turn, dip and rise as it would, the torpedo followed it. The Halliday 'planes, hovering in the air, continually menaced the victim, hampering its movements, slowing its speed.

Presently the torpedo appeared to gain some objective. For a moment it hung immediately under the 'plane, then darted up, and, for a brief moment, hung on the metal of its opponent.

The 'plane stopped as if struck; then, before the wondering eyes of the group in the square appeared to disintegrate. It disappeared in a moment and into the city fell a rain of glistening metal dust.

The sudden annihilation of the 'plane struck panic into its companions. They broke formation and sought safety in flight. The sky became dotted with single combats. But Dr. Night's aeroplanes were useless before the new Halliday machines, which were faster and more easily manoeuvred. One by one the Asian's 'planes were destroyed or driven down in the open country and captured.

The man on the throne made no answer, continuing to stare up into the sky in which now hung alone the Doris.

The newspaper man looked down on the prostrate form of the detective. He bent over him. Was the man dead? No. He was breathing steadily and regularly. Hardy shook him by the shoulder, roughly.

Inspector Frost opened his eyes, drowsily; then raised himself on his elbow and stared around him.

"I slipped, didn't I?" With a groan, as if bruised bones and muscles ached, he gained his feet. "Why, what's happened?"

Something was happening to the man. His body tensed and then relaxed. With hands clutching the ivory arms of his throne, Dr. Night pulled himself to his feet, gazing down at the little group at the foot of his throne.

"To you, Robert Hardy, farewell." The voice sounded hollow and forced. "Fate fought between you and I and the dice favoured you. Farewell, I say. I go to join those who went before me."

"The gods have blessed you, Robert Hardy." The cold voice had grown very thin. "They have chosen. You and yours to live and prosper; I to travel through the valley of ghosts to—to where Time is not."

The figure relaxed, almost falling back into the wide seat of the throne. Frost bounded up the steps and bent over the still figure. He turned to Hardy, wonderment in his eyes.

"Dr. Night is—" he hesitated, standing with one hand on the shoulder of the man he had pursued so long and relentlessly.

For a long time there was silence. Then very gently Doris took her husband's arm and led him from the city.

SLOWLY the giant 'plane came up from the land of the Seven Rivers. In the big cabin Hardy and Doris stood gazing through the window.

Not a living being showed in the silent streets of the great white city as the 'plane passed slowly over it. Only there rested on the huge throne in the centre of the white square the slight grey figure, sleeping the last sleep of all humans, seated on the throne of his ancestors he had through life coveted.

"Poor Dr. Night!" Doris's eyes filled with tears as she looked down on the city of the dead. "Should we have left him like that?"

"Yes." Her husband spoke abruptly. "He is of the past; we have the future—we—and them."

He pointed through the open door to where Roy and Ruth stood. They were not looking down on the City of the Gods—the city forgotten. Their eyes quested a city and land they would always love and remember.

The 'plane flew south. From all points of the compass victorious and conquered 'planes gathered in their wake. In the west the sun slowly declined..

"Look, Doris!" Hardy turned his wife to where the white City of the Gods was slowly disappearing below the horizon. "Vale, Dr. Night!"

"Farewell, Dr. Night." The girl's eyes filled with tears as she hid her face on her husband's shoulder.

AIDAN DE BRUNE

WHISPERING DEATH

BOOK THREE OF THE "DR. NIGHT" TRILOGY

WITH 30 ILLUSTRATIONS FROM THE WORLD'S NEWS

TABLE OF CONTENTS