Straight to that familiar room at the end of the hall I went, with Strange behind me. When we had entered, he closed the door cautiously.

For a moment he faced me without speaking.

"You came very close to committing a murder on your way here, did you not, Dale?"

I stared at him. How, in G.o.d's name, could this man read my thoughts so completely?

"You would have completed the murder," he said softly, "had I wished it.

I did not wish it!"

I did not answer. There was no reply to such a mad declaration. As for my companion, he watched me for an instant and then laughed. He was not mad. I am doctor enough to know that.

But the laugh was not long in duration. He stepped forward suddenly and took my arm in a steel grip, dragging me toward the half hidden door at the farther end of the room.

"I shall not keep you long, Dale," he said harshly. "I could have killed you--could have made you kill yourself, and in fact, I intended to do so--but after all, you are merely a poor stumbling fool who has meddled in things too deep for you."

He pulled open the door and pushed me forward. The room was dark, and not until he had closed the door again and switched on a dim light, could I see its contents.

Even then I saw nothing. At least, nothing of importance to an unscientific mind. There was a low table against the wall, with a profusion of tiny wires emanating from it. I was aware that a cup shaped microphone--or something very similar--hung over the table, about on a level with my eyes, had I been sitting in the chair. Beyond that I saw nothing, until Strange had moved forward and drawn aside a curtain that hung beside the table.

"I made you come here to-night, Dale," he murmured, "because I was a bit afraid of you. Your comrade, Hartnett, was an ignorant police officer.

He has not the intellect to connect the series of events of the past day or two, and so I did not trouble myself with him. But you are an educated man. You have made no demonstrations of your ability in the field of science, but--"

He stopped speaking abruptly. From the room behind us came the sound of a warning bell. Strange turned quickly and went to the door.

"You will wait here, Doctor," he said. "I have another caller to-night.

Another one who came the same way as you!"

He vanished. For a short interlude I was alone, with that peculiar radio-like apparatus before me. It was, for all the world, like a miniature control room in some small broadcasting station. Except for the odd shape of the microphone, if it was such I could detect no radical difference in equipment.

However, I had little time for conjecture. A patter of footsteps interrupted me from the next room, and a frightened, feminine voice broke the stillness of the outer study. Even before the owner of that voice stepped in to my presence, I knew her.

And when she came, with white, fearful face and trembling body, I could not withhold a shudder of apprehension. It was the young woman who had come to my office--Margot Vernee. Evidently, at last, she had yielded to the horrible impulse that had drawn her back to Michael Strange, an impulse which, I now understood, had originated from the man himself.

He pressed her forward. There was nothing tender in his touch: it was cruel and triumphant.

"So you have succeeded--at last," I said bitterly.

He turned to me with a sneer.

"I have brought her here, yes," he replied. "And now that she has come, she shall hear what I have to tell you. It will perhaps give her a respect for me, and this time she will not have the power to turn me away."

He pointed to the table, to the apparatus that lay there.

"I'm telling you this, Dale," he said, "because it gives me pleasure to do so. You are enough of a scientist to appreciate and understand it.

And if, when I have finished, I have told you too much, there is a very easy way to keep your tongue silent. You have heard of hypnotism, Dale?

You have heard also of radio? Have you ever thought of combining the two?"

He faced me directly. I made no effort to reply.

"Radio," he said quietly, "is broadcast by means of sound waves. That much you know. But hypnotism too, can be transmitted through distance, if an instrument delicate enough to transmit _thought waves_ can be invented. For twenty years I have worked on that instrument, and for twenty years I have studied hypnotism. You understand, of course, that this instrument is worthless unless it is operated by a master mind.

Thought waves are useless; they will not control the actions of even a cat. But hypnotic waves or concentrated thought waves--will control the world."

There was no denying him. He faced me with the savage triumph of a wild beast. He was glorying in his power, and in my amazement.

"I wanted Franklin White to die!" he cried. "It was I who murdered him.

Why? Because he was about to take the girl I desired. Is that not reason enough for murder? And so I killed him. It was not Margot Vernee who strangled her lover: it was a complete stranger, a London sportsman, who had no reason for committing the murder, _except that I wished him to_!

"He died on the night of December seventh, murdered by Sir John Harmon, the sportsman. Why? Because, of all London, Sir John would be the last man to be suspected. I have a keen appreciation for the irony of fate!

White would have died the night before, Dale, except that I lacked the courage to kill him. His murderer was standing, under my power, outside his very house--and then I suddenly thought it best that I should have an alibi. Your Scotland Yard is clever, and it was best that I have protection. And so, on the following night, I sent Sir John to the house once again. This time, while I sat here and controlled the actions of my puppet, a group of men sat here with me. They believed that I was experimenting with a new type of radio receiver!"

Michael Strange laughed, laughed harshly, in utter triumph, as a cat laughs at the antics of his mouse victims.

"When that murder was done," he said, "I sent Margot to the scene, so that she might see her lover strangled, dead. I repeat, Dale, that I enjoy the irony of fate, especially when I can control it. And as for you--I brought you here to-night merely so that you would realize the intensity of the powers that control you. When you leave here, you will be unharmed--but after the exhibition I shall give you, I am sure that you will make no further attempt to interfere with things out of your realm of understanding."

I heard a sob from Margot. She had retreated to the door, and clung there. For myself, I did not move. Strange's recital had revealed to me the horrible l.u.s.t that gripped him, and now I watched him in fascination. He would not harm the girl; that much I was sure of. In his distorted fashion he loved her. In his crazed, murderous way he would attempt to win her love, even though she had once scorned him.

I saw him step toward the table. Saw him drop heavily into the chair, and stare directly into that microphonic thing that hung before his eyes. As he stared, he spoke to me.

"Science, in its intricate forms, is probably above the mind of a common medical man, Dale," he said. "It would be useless to explain to you how my thoughts--and my will--can be transmitted through s.p.a.ce. Perhaps you have sat in a theater and stared at a certain person until that person turned to face you. You have? Then you will perhaps understand how I can control the minds of any human creature within the radius of my power.

You see, Dale, this intricate little machine gives me the power to transform London into a city of stark murder. I could bring about such a horrible wave of crime that Scotland Yard would be scorned from one end of the world to the other. I could make every man murder his neighbor, until the streets of the city were running with blood!"

Strange turned quietly to look at me. He spoke deliberately.

"And now for the little exhibition of which I spoke, Dale," he murmured.

"Your detective friend, Hartnett, has been under my power for the past three hours. You see, it was safer to control his movements, and be sure of him. And now, to be doubly sure of him, perhaps you would like to see him kill himself!"

I stepped forward with a sudden cry. Strange said nothing: his eyes merely burned into mine. Once again I felt that strange, all-powerful control forcing me back. I retreated, step by step, until the wall stopped me. Yet even as I retreated, a childish hope filled me. How could Strange, working his terrible murder machine, concentrate his power on any individual, when the whole of London lay before him?

He answered my question. He must have read it as it came over me.

"Have you ever been in a crowd, Dale, and watched a certain individual intently, until that particular individual turned to look at you? The rest of the crowd pays no attention, of course, but that one man. And now we shall make that one man murder himself!"

Strange turned slowly. I saw his fingers creep along the rim of the table, touching certain wires that came together there. I heard a dull, droning hum fill the room, and, over it, Strange's penetrating voice.

"When I am finished, Dale, I shall probably kill you. I brought you here merely to frighten you, but I believe I have told you too much."

With that new horror upon me, I saw my captor's lips move slowly....