“Look here, Datchet, I don’t know if you’re having a joke with me, or if you’re not well—­”

The duke stepped impatiently into the roadway.

“Ivor, you’re a fool!  Can’t you tell jest from earnest, health from disease?  I’m off!  Are you coming with me?  It would be as well that I should have a witness.”

“Where are you off to?”

“To the other end of the Arcade.”

“Who is the gentleman you expect to have the pleasure of meeting there?”

“How should I know?” The duke took a letter from his pocket—­it was the letter which had just arrived.  “The fellow is to wear a white top hat, and a gardenia in his buttonhole.”

“What is it you have there?”

“It’s the letter which brought the news—­look for yourself and see; but, for God’s sake, make haste!” His grace glanced at his watch.  “It’s already twenty after five.”

“And do you mean to say that on the strength of a letter such as this you are going to hand over five hundred pounds to—­”

The duke cut Mr. Dacre short.

“What are five hundred pounds to me?  Besides, you don’t know all.  There is another letter.  And I have heard from Mabel.  But I will tell you all about it later.  If you are coming, come!”

Folding up the letter, Mr. Dacre returned it to the duke.

“As you say, what are five hundred pounds to you?  It’s as well they are not as much to you as they are to me, or I’m afraid—­”

“Hang it, Ivor, do prose afterwards!”

The duke hurried across the road.  Mr. Dacre hastened after him.  As they entered the Arcade they passed a constable.  Mr. Dacre touched his companion’s arm.

“Don’t you think we’d better ask our friend in blue to walk behind us?  His neighborhood might be handy.”

“Nonsense!” The duke stopped short.  “Ivor, this is my affair, not yours.  If you are not content to play the part of silent witness, be so good as to leave me.”

“My dear Datchet, I’m entirely at your service.  I can be every whit as insane as you, I do assure you.”

Side by side they moved rapidly down the Burlington Arcade.  The duke was obviously in a state of the extremest nervous tension.  Mr. Dacre was equally obviously in a state of the most supreme enjoyment.  People stared as they rushed past.  The duke saw nothing.  Mr. Dacre saw everything, and smiled.

When they reached the Piccadilly end of the Arcade the duke pulled up.  He looked about him.  Mr. Dacre also looked about him.

“I see nothing of your white-hatted and gardenia-buttonholed friend,” said Ivor.

The duke referred to his watch.

“It’s not yet half-past five.  I’m up to time.”

Mr. Dacre held his stick in front of him and leaned on it.  He indulged himself with a beatific smile.

“It strikes me, my dear Datchet, that you’ve been the victim of one of the finest things in hoaxes—­”