“Bless my soul,” Charles cried, “so she does!  And it’s now past ten!  The carriage will be at the door for us in another five minutes!”

Next morning, accordingly, Charles drove round to Marvillier’s.  The famous detective listened to his story with glistening eyes; then he rubbed his hands and purred.  “Colonel Clay!” he said; “Colonel Clay!  That’s a very tough customer!  The police of Europe are on the look-out for Colonel Clay.  He is wanted in London, in Paris, in Berlin.  It is le Colonel Caoutchouc here, le Colonel Caoutchouc there; till one begins to ask, at last, IS there any Colonel Caoutchouc, or is it a convenient class name invented by the Force to cover a gang of undiscovered sharpers?  However, Sir Charles, we will do our best.  I will set on the track without delay the best and cleverest detective in England.”

“The very man I want,” Charles said.  “What name, Marvillier?”

The principal smiled.  “Whatever name you like,” he said.  “He isn’t particular.  Medhurst he’s called at home. We call him Joe.  I’ll send him round to your house this afternoon for certain.”

“Oh no,” Charles said promptly, “you won’t; or Colonel Clay himself will come instead of him.  I’ve been sold too often.  No casual strangers!  I’ll wait here and see him.”

“But he isn’t in,” Marvillier objected.

Charles was firm as a rock.  “Then send and fetch him.”

In half an hour, sure enough, the detective arrived.  He was an odd-looking small man, with hair cut short and standing straight up all over his head, like a Parisian waiter.  He had quick, sharp eyes, very much like a ferret’s; his nose was depressed, his lips thin and bloodless.  A scar marked his left cheek—­made by a sword-cut, he said, when engaged one day in arresting a desperate French smuggler, disguised as an officer of Chasseurs d’Afrique.  His mien was resolute.  Altogether, a quainter or ’cuter little man it has never yet been my lot to set eyes on.  He walked in with a brisk step, eyed Charles up and down, and then, without much formality, asked for what he was wanted.

“This is Sir Charles Vandrift, the great diamond king,” Marvillier said, introducing us.

“So I see,” the man answered.

“Then you know me?” Charles asked.

“I wouldn’t be worth much,” the detective replied, “if I didn’t know everybody.  And you’re easy enough to know; why, every boy in the street knows you.”

“Plain spoken!” Charles remarked.

“As you like it, sir,” the man answered in a respectful tone.  “I endeavour to suit my dress and behaviour on every occasion to the taste of my employers.”

“Your name?” Charles asked, smiling.

“Joseph Medhurst, at your service.  What sort of work?  Stolen diamonds?  Illicit diamond-buying?”

“No,” Charles answered, fixing him with his eye.  “Quite another kind of job.  You’ve heard of Colonel Clay?”