CHAPTER IV

Blackmail

Carton spoke softly through the darkness to the man beside him as their car stopped. "Is this the place, Wade?"

Wade nodded. "There's the milestone--you're ready, Grantham?"

Grantham nodded. "All ready--Kingston has the box."

As they emerged from the car onto the road that gleamed white in the darkness, Carton glimpsed behind it other cars from which dark shapes of men were emerging, rifles and pistols gleaming in their hands. All had turned off their lights, and the scrubby woods that rose on either side of the road seemed impenetrable walls of blackness.

It had been little more than a day, Carton reflected as he stood in the road with the others, since the Invisible Master's astonishing demand had been received by the New York authorities. There had been no doubt or dispute whatever as to whether that demand should be met. With wild crowds besieging the City Hall, with all New York's customary organized life sinking into chaos beneath the panic-pall of the Invisible Master's presence, there was no other course to follow, and a subscription for raising the money had instantly been started.

Through the rest of that day and the next the money had poured in, mostly in great sums from the banks and big business houses of the city who realized that it was only by payment of this tribute that the metropolis could be saved from chaotic ruin. Later on, they reasoned, the Invisible Master could be hunted down and dealt with, but now the thing was to lift his menace from New York. Five millions was a great sum, but not in comparison with the daily loss the city's businesses were undergoing. By the next afternoon the five millions were ready, a compact mass of securities and highest-denomination bills.

It had been placed in the specified small steel box, and given into the charge of Kingston, a representative of the city's government who was to place the money as requested. And since the Invisible Master had mockingly given full permission for any to attempt his capture who wished to, Wade and Grantham had worked out the scheme that held a slender chance of trapping the unseen criminal. With their two-score of armed men waiting behind them, Grantham explained the plan in the lowest of voices to Carton and Kingston.

"Kingston and I will take the box in and place it on the boulder," he whispered, "and when we do so I'll stretch in a circle of yards around it this thread of wire, and connect it to this pocket-battery and bell. Kingston and I will wait with the money, behind the big oak, and Wade's men will lie in a circle all around the spot.

"When the Invisible Master comes he'll make for the boulder, and must necessarily strike the stretched wire and ring the bell just before he reaches it. Then your men can rush in from all sides to enclose him in their circle, while Kingston and I will be there and armed to prevent the money from being taken by him. It's our one hope of catching him, for we'll never have this chance again, I think."

The Trap

Wade nodded. "We all understand the plan, Grantham. We'll wait for him if it takes until daylight."

"I think he'll appear tonight," Grantham said. "I imagine he is rather anxious to get the money and have it all over with."

"Well, good luck," whispered Wade, extending his hand, which the physicist grasped. Kingston too, a little nervously, shook hands with the officer, and then the two disappeared silently into the dark wall of the wood eastward.

Wade and Carton waited for a moment as silent as the grouped silent men behind them, and then as Wade passed a whispered order to them, they all were melting into the dark forest likewise. Swiftly they formed a circle of a hundred feet in radius around the great oak at whose foot was the stone the Invisible Master had specified. On that stone by then, Carton knew, the steel box would be resting, with Grantham and Kingston watching from close beside for the warning bell. The circle of men had in a moment crouched down here and there in the brush, Wade beside Carton, and the wood settled back into its accustomed night silence.

The trap was ready. Would the Invisible Master dare to enter it?

Carton remembered afterward the time of waiting that followed as a period of almost infinite length. Crouching silent and motionless with Wade in a clump of brush he listened tensely. Out to right and left of him, he knew, were crouching the dozens of men who made up the circle, each ready with rifle or pistol and electric torch, each listening as intently as themselves. And at the circle's center, Grantham and Kingston. All waiting for the unseen man who was to come to claim the price of the terror he had loosed upon New York.

Was it a twig that snapped somewhere to the left, Carton wondered? Every slightest sound seemed intensified in the unnatural stillness of the place. A half-hour had passed but there came still no alarm. Wade was chewing gum as softly and silently as ever beside him, his heavy pistol ready in his hand. The desolate hum of crickets came to their ears.

Through the branches above Carton could see the moon drifting past. He began to try estimating by it how long they had waited. Then suddenly a sound came that shattered the stillness of the woods as with a tangible blow. The jangling of a bell!

"At him!" Wade cried as they leapt up, forward. All around them the dark shapes of men were running toward the towering oak!

They heard hoarse cries from Kingston and Grantham ahead--a single brief exclamation in a deeper voice--and then--crash!--crash!--crash! three shots echoing through the forest from ahead like the crash of cannon!

"He's there--don't let him get through!" Wade cried. The circle of running men was contracting and merging in an instant upon the central oak. Their guns leapt in their hands as they burst into the little clearing beneath it. They stopped.

Kingston lay on the ground in a grotesque attitude beneath the light of their torches, shot through the heart. Grantham, blood welling from his left shoulder, was twisted in a half-sitting position beside him. There was no one else in the clearing and of the steel box that had rested on the boulder there was no sign!

"He got it!" Grantham whispered, his face distorted with pain. "He got it and got away--the Invisible Master!"

"Beat the woods!" Wade's voice flared. "Carry your torches and shoot at every sound of steps when there's no one visible with them! He's slipping out somewhere now!"

Grantham shook his head. "No use," he said. "We can't fight him, Wade. Kingston and I were crouched behind the oak with our wire ready, and we heard the bell ring, then as we leapt forward an instant later saw the steel case disappearing from off the stone! Kingston had grasped him, I think, was struggling with something invisible as we both cried out, and I heard an exclamation from him and then the shots roared out of the empty air just beside Kingston. Kingston fell like a stone, I heard one of the shots rip past me and another caught my shoulder. Then I heard the sound of leaping feet beside me just a moment before you burst into the clearing."

Whose Voice?

"But you heard his voice close beside you!" Wade exclaimed. "Was it Gray's?"

Grantham's pale face took on a certain puzzlement. "It may have been, Wade--I heard it for but an instant in that exclamation--I don't know whether that was Gray's or another's, it was a voice I had heard often before."

Wade nodded decisively. "That ends all doubt as to it's being Gray, at least. Carton, do what you can for Grantham's shoulder, while I see if any of the men have run across him."

But in minutes the men were streaming back with Wade, their search fruitless. They had found no one--could have found no one, Carton realized, in that search through the darkness for a being invisible. Wade shook his head.

"It's all over," he said, "and I realize now that we never really had a chance of capturing him. We can only hope that he'll be content with the five million and never again loose terror on any city as he did upon New York. Five millions--well, it may be best, after all."

Silently the party drove back to the city, and after they had taken Grantham to his rooms near the university and summoned a doctor for his wound, Carton and Wade rode together downtown. It was with a rueful shake of the head on the detective's part that they parted; he to his headquarters and Carton to the _Inquirer's_ city-room to pound out an abridged account of the night's events. By the time that Carton went wearily across the city to his own rooms newsboys were shouting in the streets the welcome news that the Invisible Master had been bought off and that his reign of terror was ended.

Carton, in his tired sleep, lived again the tense events of the night, and it seemed to his sleep-numbed mind that the warning bell they had heard was jangling again and again. It woke him finally, to find that it was his doorbell, and when he opened it Wade stood before him. The detective's sleepy eyes were more wakeful than ever Carton had seen them, but to the reporter's first excited question he snapped but a single order.

"Dress, Carton--we're going up to the university."

In minutes they were flying out along Riverside Drive through the growing morning sunlight. Around them the city was waking to a day of heart-felt rejoicing that the terror was lifted. Wade seemed the container of a strange grim force, and to Carton's questions returned no answer. But when they had drawn up before the familiar gray physics building and had entered the equally familiar little laboratory and ante-room, Carton found Grantham awaiting them, his shoulder bound and his face haggard from a sleepless night.

"You called me, Wade?" he asked. "Something you'd found?"

Wade nodded. "Yes. But first I'd like to have President Ellsworth here. He's near here, isn't he?"

Grantham nodded, frowning. "His home is--yes. I heard he'd been away for a day or two but he ought to be back by now."

He turned to the telephone, spoke briefly into it, and when he had finished turned to Wade. "He's coming," he said.

They sat silent until President Ellsworth entered minutes later. As he came in Carton noted that the two officers who had accompanied Wade and himself were lounging in the hall outside. The President's ordinarily genial face held some irritation.

Wade Makes a Statement

"What's this--a sort of post-mortem?" he asked. "I've just heard all about last night, Sergeant Wade--and it was too bad that the Invisible Master slipped through yours and Grantham's hands. But perhaps it's best that it's all over."

"It is not all over yet," Wade said quietly.

Ellsworth stared, as did Grantham and Carton. "You mean--" the President began.

"I mean that I know at last who the Invisible Master is and where he is!" said Wade.

Ellsworth seemed too astounded to speak, but Grantham leaned to grasp Wade's arm. "Is that true, Wade?" he asked. "You've actually found him?"

"I have," Wade told them quietly.

And then as the three others stared at him he went on. "You remember, Grantham, that you told me that in a case like this the ordinary police-routine, the gathering of fact after fact to apprehend a criminal, was useless? You may have been right, but I followed that routine and I've finally gathered among other facts, three facts that tell me everything I want to know about the Invisible Master. Had I had these three facts last night I could have saved us that struggle and Kingston's life, but I did not have them then. I have them now, though."

"And the three facts?" Grantham asked. Ellsworth was staring as though bewilderedly, Carton leaning tensely forward.

"The first fact," said Wade, "is something that President Ellsworth happened to say the other night--when we spoke of Gray--saying how Grantham and he had been hampered in their scientific work by lack of funds, and how it would be almost justifiable to take some of the city's pleasure-spent millions for the aiding of research."

They were all silent. Ellsworth's face had flushed.

"The second fact is one that not all of you may understand and that I myself was ignorant of until last night--it is the peculiar optical properties of tourmaline crystals."

Carton and Ellsworth stared at him blankly, but Grantham's eyes gleamed with sudden understanding.

"The third fact, which I also learned last night and which is the most significant perhaps of all, is the simple record of a stockbroker's account carried some weeks ago by Mr. Peter Harkness."

Wade was silent, and Carton, astounded and bewildered, could only stare at him still. Ellsworth was about to burst into questions but was interrupted by Grantham's voice. The physicist had risen and turned from them toward the window. His voice came over his shoulder to them.

"I think I can give you a fourth fact that will clinch it, Wade." His right arm crooked--

Wade leapt, but an instant too late. For when he spun Grantham around the physicist was already falling, his lips writhing with cyanide grains still upon them, a faint peachy odor in the air. He was still, dead, when Wade lowered his body to the floor. The detective straightened, mopping his brow.

"I was afraid of that," he panted. "I was afraid of it--but damned if I don't think it was his best way out!"

Carton and Ellsworth gazed as though petrified. Then Carton's voice--shaking--

"Then Grantham--Grantham himself--was the Invisible Master?"

Wade turned.

"There never was any Invisible Master at all," he said.

Back to the Laboratory

Carton and Ellsworth stared at him for moments before they could speak.

"But Grantham's power of making things invisible!" Carton finally cried. "We saw him do it here--"

Wade shook his head. "You didn't Carton, but you thought you did."

He strode to the laboratory's long table, they with him. He searched along it for a time and found what he sought, a round disk of glass-like material, clear and transparent. He placed it against one small pane of the window, through which the sunlight was pouring, and to their amazement it showed black and opaque against the sunlight. Wade slowly turned the disk in his hand, keeping its flat side parallel to the window. As he turned it, it became less and less opaque until by the time he had given it a quarter-turn it was completely transparent, and was in fact wholly invisible because of the brilliant sunlight streaming through it from behind into their eyes!

Slowly Wade revolved the disk another quarter-turn and as he did so it became cloudy and translucent and then more and more opaque until at the end of the half-turn it was as dead black and visible against the sunlight as ever! Carton and Ellsworth stared unbelievingly, and Wade handed the disk to them.

"A tourmaline-crystal," he said. "There's another set in that small window pane. Their property is well enough known to physicists, and is a result and proof of the polarization of light. When two tourmaline crystals are placed together with their axes parallel, light streams through both unchecked. If one is turned so that its axis is at right angles to the axis of the other, though, light cannot pass through them and they become thus opaque. A quarter-turn of the one will make them transparent again.

"Grantham had one tourmaline-crystal set in the window-pane and the other in the disk form. He showed you the black glass paper-weight disk he was going to make invisible, but when he leaned forward to put it on the little projector he palmed it and put there instead this tourmaline disk. It showed black, like the paper-weight, though, because he placed it on the projector's framework with axis at right angles to that of the crystal in the window-pane.

"The sunlight was coming straight through the window into your eyes (he had chosen the hour), and you saw the black disk against it, resting on the projector's framework. Grantham and Gray had some sort of mechanism inside the projector to make an appropriate sound, but the switches Grantham turned actually controlled the framework above the projector, which was made so as to turn the disk resting in it a quarter-turn when desired.

"You see how it was done? Grantham turned his switches, and as the tourmaline disk was turned slowly in its framework you saw it growing more and more transparent until when it had been turned a quarter-turn in the framework it was perfectly transparent and so invisible to your eyes in the strong sunlight streaming through it. Grantham let it remain so but a moment and then with his switch or rheostat control turned it back again a quarter-turn. It grew more and more cloudy and black until at a quarter-turn it was again black and opaque against the light. He reached for it, and when he turned to you again palmed it and could hand you the paper-weight disk."

Carton shook his head like one dazed. "And it seemed such a perfectly open demonstration," he said.

"But that doesn't explain the Invisible Master!" Ellsworth exclaimed. "If Grantham's power was faked, who committed those three crimes that no one but an invisible person could have committed? Who took the money last night?"

Wade Reconstructs

"I think I can reconstruct the thing from the first," Wade said, "though some of the secret died with Grantham here. You told me yourself that he and Gray had long been prevented from engaging in the lines of research they desired because of their lack of funds. Well, I think that Grantham grew resentful at this, and then determined, and that he and Gray resolved to lay hands on the money they needed in their own fashion. To do it they worked out an elaborate and incredibly ingenious plan, that hinged upon Grantham's known reputation as a great physicist.

"Grantham and Gray prepared the tourmaline-crystal set-up, and then let it be known in one way or another that Grantham had discovered a method of making things invisible. Of course there was excitement, and of course the reporters, Carton among them, rushed out here to learn all about it. Then Grantham reluctantly consented to a demonstration, and after pulling this tourmaline-crystal stunt, sent them away, and you too, perfectly convinced that he had actually found a way to make matter invisible. That was his first great step--to implant in the minds of reputable witnesses the absolute conviction that he had really the power of making things invisible.

"Just what happened on that afternoon between Grantham and Gray may never be known fully, but there seems little doubt that Gray, who had been sullen at the demonstration that morning, had come to the point where he had resolved not to go on with the scheme. Probably he threatened to expose Grantham if he did not stop it, and no doubt Grantham saw exposure and oblivion on the way. Fearing Gray's confession, he killed him, and disposed of his body here in the laboratory. He had the knowledge to do that, and I've found that on that afternoon he received from the supply-rooms here an inordinate order of acids which were without doubt used in the disposition of Gray's body. However it was done, there is not the slightest doubt that on that afternoon Gray, and even his body, passed out of existence in this laboratory.

"Then Grantham went on with his plan, changing it somewhat, no doubt, to fit in with this new circumstance. That night he struck himself a painful but not heavy blow on the head with some wooden object--you remember the doctor said the blow was from the side?--and pretended to be lying stunned when you, President Ellsworth, came in. When the police came he, without seeming to want to do so, threw the responsibility of the attack on Gray as much as possible, and told of his projector that had been stolen by his attacker, and that would make a man invisible. He had already prepared a mocking letter addressed to himself as from the Invisible Master, and while talking with Carton and me, laid the letter on the table where I found it. The officers at the door had seen no one go in or out, we knew or thought we knew that someone was at large with an apparatus for attaining invisibility, and since we never dreamed of Grantham having left the letter, we had no doubt whatever but that the Invisible Master, whether Gray or another, had actually entered the room invisibly and left the letter for us.

"This was Grantham's second step, his establishing the idea that someone was at large with a projector that could make him invisible, that the Invisible Master was at large and ready to commit any crime. That idea was established in all the city by the newspapers in the next day or so, and so strong was the evidence in the demonstration of his discovery that Grantham had given, and the greatness of his reputation as a scientist, that almost all did believe that such an invisible man, an Invisible Master, was at large.

"Now what would naturally result when almost all in the city believed that? Would it not result in many people seeing a chance to commit crimes and then blame them on the Invisible Master? You know that there are hundreds of thousands in a city like this who long to commit some crime, theft or murder or the like, but dare not because there would be no chance to shift suspicion on someone else. A man in an apartment with neighbors all around can't shoot his wife and claim someone else came in and did it, for he knows that in ninety-nine cases out of a hundred it would soon be established that no one had gone in or out of his apartment at that time. But if he could blame it on someone invisible? You see what it means? Grantham had spread, had insisted upon spreading, over all the city the thought that the Invisible Master was at large in it. So at once there would be countless people who would see a chance to commit crimes and blame them on the Invisible Master! The thing was as certain as human nature!