"One moment, girls," he said. "I see now how he did it. Wait. I'll show you."

They stood quite still, a little terrified. In a moment or two the door reopened. A finger turned out all the electric lights but one. Then there was nothing to be seen but a pair of white hands, which seemed to come floating towards them through the darkness--a pair of white hands and a pair of gleaming eyes. Lenora screamed wildly. Even Laura was unnerved.

"Stop that!" she cried out. "Who are you, anyway?"

The lights were suddenly turned on. Quest threw off his disguise.

"There you are," he exclaimed triumphantly. "Ingenious, but one ought to have seen through it long ago. The stroke of genius about it was that as soon as he had used a dodge once or twice and set you thinking about it, he dropped it."

The door was suddenly opened and French entered.

"Beaten!" he exclaimed tersely.

"You haven't found him?" Quest asked.

French shook his head.

"We've searched every room, every cupboard, every sc.r.a.p of the cellar in the house," he announced. "We've been into every corner of the grounds, searched all the place inside and out. There's no sign of the Professor."

Quest pocketed the diary.

"You're perfectly certain that he is not in this house or anywhere upon the premises?"

"Certain sure!" French replied.

Quest shrugged his shoulders.

"Well, we'd better get back," he said. "You come, too, French. We'll sit down and figure out some scheme for finding him."

They made their way to the front door and crowded into the autos. The two men left with marked reluctance. The two girls had but one idea in their heads--to get away, and get away quickly.

"Do start, please," Lenora begged. "There's just one thing in life I want, and that is to be in my own room, to feel myself away from his world of horrible, unnatural mysteries."

"The kid has the right idea," Laura agreed. "I've had enough myself."

They were on the point of starting, the chauffeur with his hand upon the starting handle, French with the steering wheel of the police car already in his hand. And then the little party seemed suddenly turned to stone.

For a few breathless seconds not one of them moved. Out into the clammy night air came the echoes of a hideous, inhuman, blood-curdling scream.

Quest was the first to recover himself. He leaped from his seat and rushed back across the empty hall into the study, followed a little way behind by French and the others. An unsuspected panel door which led into the garden, stood slightly ajar. The Professor, with his hand on the back of a chair, was staring at the fireplace, shaking as though with some horrible ague, his face distorted, his body curiously hunched-up. He seemed suddenly to have dropped his humanity, to have fallen back into the world of some strange creatures. He heard their footsteps, but he did not turn his head. His hands were stretched out in front of him as though to keep away from his sight some hateful object.

"Stop him!" he cried. "Take him away! It's Craig--his spirit! He came to me in the garage, he followed me through the grounds, he mocked at me when I hid in the tree. He's there now, kneeling before the fireplace. Why can't I kill him! He is coming! Stop him, some one!"

No one spoke or moved; no one, indeed, had the power. Then at last Quest found words.

"There is no one in the room, Professor," he said, "except us."

The sound of a human voice seemed to produce a strange effect. The Professor straightened himself, shook his head, his hands dropped to his side. He turned around and faced them. He was ghastly pale, but his smile was once more the smile of the amiable naturalist.

"My friends," he said, "forgive me. I am very old, and the events of these last few hours have unnerved me. Forgive me."

He groped for a moment and sank into a chair. Quest fetched a decanter and a gla.s.s from the sideboard, poured out some wine and held it to his lips.

The Professor drank it eagerly.

"My dear friend," he exclaimed, "you have saved me! I have something to tell you, something I must tell you at once, but not here. I loathe this place. Let me come with you to your rooms."

"As you please," Quest answered calmly.

The Professor rose hastily to his feet. As he turned around, he saw French concealing something in his hands. He shivered.

"I don't need those!" he cried. "What are they? Handcuffs? Ah, no! I am only too anxious to tell you all that I know. Take care of me, Mr. Quest.

Take me with you."

He gripped Quest's arm. In silence they pa.s.sed from the room, in silence they took their places once more in the automobiles, in silence they drove without a pause to Quest's rooms. The Professor seemed to breathe more freely as they left the neighbourhood of his house behind. He walked up the stairs to Quest's library almost blithely. If he was aware of it, he took no notice of French and the two plain-clothes men behind. As he stepped into the room, he drew a long sigh of relief. He made his way at once to his favourite easy-chair, threw off his overcoat and leaned back.

"Quest," he p.r.o.nounced, "you are the best friend I have in my life! It is you who have rid me of my great burden. Tell me--help me a little with my story--have you read that page from the _Medical Journal_ which Craig has kept locked up all these years?"

"We have all read it," Quest replied.

"It was forged," the Professor declared firmly, "forged by Craig. All the years since, he has blackmailed me. I have been his servant and his tool.

I have been afraid to speak. At last I am free of him. Thank G.o.d!"

"Craig, after all," French muttered.

The Professor sat with a faint, wistful smile upon the corners of his lips, looking around at all of them. His face had become like the face of a child, eager for sympathy and kindness.

"You will trust me, I know," he continued. "You will believe me. All my life I have laboured for science. I have never been selfish. I have laid up no store of gold or treasure. Knowledge has been my mistress, knowledge has been my heaven. If I had been a wise man, I would have ridden myself of this hideous burden, but I was foolish and afraid. I wanted to pursue my studies, I wanted to be left in peace, so I let that fiend prey upon my fears. But now--now I feel that the burden has rolled away. I shall tell you my story, and afterwards I will do great things yet, great things for science, great things for the world."

They listened to him, spellbound. Only Lenora stood a little apart with a faint frown upon her forehead. She touched Quest on the shoulder.

"Mr. Quest," she murmured, "he is lying!"

Quest turned his head. His lips scarcely moved.

"What do you mean?" he whispered.

"He is lying!" Lenora insisted. "I tell you there's another creature there, something we don't understand. Let me bring the Electro-thought transference apparatus; let us read his mind. If I am wrong, I will go down on my knees and beg for forgiveness."

Quest nodded. Lenora hastened to the further end of the room, s.n.a.t.c.hed the cloth from the instrument and wheeled down the little mirror with its coils and levers. The Professor watched her. Slowly his face changed. The benevolence faded away, his teeth for a moment showed in something which was almost a snarl.

"You believe me?" he cried, turning to Quest. "You are not going to try that horrible thing on me--Professor Lord Ashleigh? I am all broken up. I am not fit for it. Look at my hands, how they shake."

"Professor," Quest said sternly, "we are surrounded by the shadow of some terrible deeds for which as yet there is no explanation. I do not say that we mistrust you, but I ask you to submit to this test."

"I refuse!" the Professor replied harshly.

"And I insist," Quest muttered.

The Professor drew a little breath. He sat back in his chair. His face became still, his lips were drawn closely together. Lenora wheeled up the machine and with deft fingers adjusted the fittings on one side. Quest himself connected it up on the other. The Professor sat there like a figure of stone. The silence in the room was so intense that the ticking of the small clock upon the mantelpiece was clearly audible. The silent battle of wills seemed like a live and visible struggle. The very atmosphere seemed charged with the thrill and wonder of it. Never before had Quest met with resistance so complete and immovable. For the first time the thought of failure oppressed him. Even that slight slackening of his rigid concentration brought relief to the Professor. Without any knowledge as to the source of their conviction, the two girls who watched felt that the Professor was becoming dominant. And then there came a sudden queer change. The intangible triumph of the Professor's stony poise seemed to fade away. His eyes had sought the corner of the room, his lips quivered. The horror was there again, the horror they had seen before. He crouched a little back. His hands were uplifted as though to keep off some evil thing.