For only a little while they talked of the mystery.  While Graham regretted his failure to find any trace of Maria, their voices dwindled sleepily.  Bobby recalled his last thought before losing himself last night.  He tried to force from his mind now the threat in Robinson’s eyes.  He told himself again and again that the man wasn’t actually unfriendly.  Then the blackness encircled him.  He slept.

Almost at once, it seemed to him, he was fighting away, demanding drowsily: 

“What’s the matter?  Leave me alone.”

He heard Graham’s voice, unnaturally subdued and anxious.

“What are you doing, Bobby?”

Then Bobby knew he was no longer in his bed, that he stood instead in a cold place; and the meaning of his position came with a rush of sick terror.

“Get hold of yourself,” Graham said.  “Come back.”

Bobby opened his eyes.  He was in the upper hall at the head of the stairs.  Unconsciously he had been about to creep quietly down, perhaps to the library.  Graham had awakened him.  It seemed to offer the answer to everything.  It seemed to give outline to a monstrous familiar that drowned his real self in the black pit while it conducted his body to the commission of unspeakable crimes.

He lurched into the bedroom and sat shivering on the bed.  Graham entered and quietly closed the door.

“What time is it?” Bobby asked hoarsely.

“Half-past two.  I don’t think Robinson was aroused.”

The damp moon gave an ominous unreality to the room.

“What did I do?” Bobby whispered.

“Got softly out of bed and went to the hall.  It was uncanny.  You were like an automaton.  I didn’t wake you at once.  You see, I—­I thought you might go to the old room.”

Bobby shook again.  He drew a blanket about his shoulders.

“And you believed I’d show the way in and out, but the room was empty, so I was going downstairs—­”

He shuddered.

“Good God!  Then it’s all true.  I did it for the money.  I put Howells out to protect myself.  I was going after Robinson.  It’s true.  Hartley!  Tell me.  Do you think it’s true?”

Graham turned away.

“Don’t ask me to say anything to help you just now,” he answered huskily, “for after this I don’t dare, Bobby.  I don’t dare.”

CHAPTER VII

THE AMAZING MEETING IN THE SHADOWS OF THE OLD COURTYARD

Bobby returned to his bed.  He lay there still shivering, beneath the heavy blankets.  “I don’t dare!” He echoed Graham’s words.  “There’s nothing else any one can say.  I must decide what to do.  I must think it over.”

But, as always, thought brought no release.  It merely insisted that the case against him was proved.  At last he had been seen slipping unconsciously from his room—­and at the same hour.  All that remained was to learn how he had accomplished the apparent miracles.  Then no excuse would remain for not going to Robinson and confessing.  The woman at the lake and in the courtyard, the movement of the body and the vanishing of the evidence under his hand, Paredes’s odd behaviour, all became in his mind puzzling details that failed to obscure the chief fact.  After this something must be done about Paredes’s detention.