“Impossible!” the Professor exclaimed hoarsely.

“How can he have been here?” Lenora cried.

Quest removed the lid from the box and drew out a circular card.  Around the outside edge was a very clever pen and ink sketch of a lifebuoy, and inside the margin were several sentences of clear handwriting.  In the middle was the signature—­the clenched hands!  Quest read the message aloud—­

“In the great scheme of things, the Supreme Ruler of the Universe divided an inheritance amongst His children.  To one He gave power, to another strength, to another beauty, but to His favourites He gave cunning.”

They all looked at one another.

“What does it mean?” Lenora gasped.

“A lifebuoy!” the Professor murmured.

They both stared at Quest, who remained silent, chewing hard at the end of his cigar.

“Every message,” he said, speaking half to himself, “has had some significance.  What does this mean—­a lifebuoy?”

He was silent for a moment.  Then he turned suddenly to the Professor.

“What did you call those men in the motor-truck, Professor—­river pirates?  And a lifebuoy!  Wait.”

He crossed the room towards his desk and returned with a list in his hand.  He ran his finger down it, stopped and glanced at the date.

“The Durham,” he muttered, “cargo cotton, destination Southampton, sails at high tide on the 16th.  Lenora, is that calendar right?”

“It’s the 16th, Mr. Quest,” she answered.

Quest crossed the room to the telephone.

“I want Number One Central, Exchange,” he said.  “Thank you!  Put me through to Mr. French’s office....  Hullo, French!  I’ve got an idea.  Can you come round here at once and bring an automobile?  I want to get down to the docks—­not where the passenger steamers start from—­lower down....  Good!  We’ll wait.”

Quest hung up the receiver.

“See here, Professor,” he continued, “that fellow wouldn’t dare to send this message if he wasn’t pretty sure of getting off.  He’s made all his plans beforehand, but it’s my belief we shall just get our hands upon him, after all.  Lenora, you’d better get along round to the hospital.  You don’t come in this time.  It’s bad enough to have Laura laid up—­can’t risk you.  There’ll be a little trouble, too, before we’re through, I’m afraid.”

Lenora sighed as she picked up her bag.

“If it weren’t for Laura,” she said, “you’d find it pretty hard to keep me away.  I think that if I could see the handcuffs put on that man, it would be the happiest moment of my life.”

“We’ll get him all right,” Quest promised.  “Remember me to Laura.”

“And present my compliments, also,” the Professor begged.

Lenora left them.  The Professor, his spirits apparently a little improved by the prospect of action, accepted some whisky and a cigar.  Presently they heard the automobile stop outside and French appeared.