“A turmoil.  First of all, where is the Professor?”

“Must have scooted right away home,” French suggested.  “He was looking pretty sick all the time.  Guess it must have been a powerful shock for him, and he isn’t so young as he used to be.”

“Give me that paper of Craig’s again,” Quest asked, stretching out his hand.

The Inspector produced the document from his inner pocket, and Quest, stretching it out upon his knee, read it word for word.

“Never to communicate or to have anything to do with any one of the name of Ashleigh, eh?” he remarked, as he handed it back again.  “Rather a queer provision, that, French.”

“I’ve been thinking that myself,” the Inspector admitted.  “Seems to be rather reversing the positions, doesn’t it?”

Quest glanced at the clock.

“Well,” he said, “if you’re ready, Inspector, we’ll be getting along.”

“Where to?” French demanded.

Quest looked for a moment surprised.  Just then Lenora entered the room.

“Are you going out?” she asked Quest.

He nodded.

“The Inspector and I are going to have a look for that black box,” he told her.

“Won’t you want me?”

He shook his head.

“I think you girls have had as much as is good for you of this sort of business,” he declared grimly.

“But it’s all over now,” Lenora protested.

Quest buttoned up his coat and motioned to French to follow him.

“I’m not so sure,” he said.  “I’ll ’phone if we want you, Lenora.  We shall be at the Professor’s.”

The two men drove to the outskirts of the city almost in silence, while several of the officers followed in another taxi.  The Professor’s house seemed more than ever deserted as they drew up at the front door.  They entered without ringing and crossed the hall towards the library.  On the threshold Quest paused and held up his finger.

“Some one is in there,” he whispered, stepping quickly forward.  “Come!”

He threw open the door.  The room was empty, yet both Quest and French were conscious of a curious conviction that it had been occupied within the last few seconds.  French even shook out the curtains and swung open the doors of a bureau.  There was no sign of anybody, however, nor any evidence as to how they could have left the room.

“Queer, but it seemed to me I heard some one,” French muttered.

“I was sure of it,” Quest replied, shaking the curtains at the back of the door.

They stood still for a moment and listened.  The silence in the empty house was almost unnatural.  Quest turned away with a shrug of the shoulders.

“At any rate,” he said, “Craig’s dying thoughts must have been truthful.  Come.”

He led the way to the fireplace, went down on his knees and passed his hands over the bricks.  The third one he touched, shook.  He tapped it—­without a doubt it was hollow.  With his penknife he loosened the mortar a little and drew it out easily.  The back was open.  Inside was the black box.