“‘But—­’ he began.

“‘We won’t have any butting, your Grace,’ said I.  ’I’ll give you the watch, and you needn’t mind the L200; and you must give me the tiara, or I’ll accompany you forthwith to the police, and have a search made of your hat.  It won’t pay you to defy me.  Give it up.’

“He gave up the hat at once, and, as I suspected, there lay the tiara, snugly stowed away behind the head-band.

“‘You are a great fellow.’ said I, as I held the tiara up to the light and watched with pleasure the flashing brilliance of its gems.

“‘I beg you’ll not expose me,’ he moaned.  ’I was driven to it by necessity.’

“‘Not I,’ I replied.  ’As long as you play fair it will be all right.  I’m not going to keep this thing.  I’m not married, and so have no use for such a trifle; but what I do intend is simply to wait until your wife retains me to find it, and then I’ll find it and get the reward.  If you keep perfectly still, I’ll have it found in such a fashion that you’ll never be suspected.  If, on the other hand, you say a word about to-night’s events, I’ll hand you over to the police.’

“‘Humph!’ he said.  ‘You couldn’t prove a case against me.’

“‘I can prove any case against anybody,’ I retorted.  ’If you don’t believe it, read my book,’ I added, and I handed him a copy of my memoirs.

“‘I’ve read it,’ he answered, ’and I ought to have known better than to come here.  I thought you were only a literary success.’  And with a deep-drawn sigh he took the watch and went out.  Ten days later I was retained by the Duchess, and after a pretended search of ten days more I found the tiara, restored it to the noble lady, and received the L5000 reward.  The Duke kept perfectly quiet about our little encounter, and afterwards we became stanch friends; for he was a good fellow, and was driven to his desperate deed only by the demands of his creditors, and the following Christmas he sent me the watch I had given him, with the best wishes of the season.

“So, you see, gentlemen, in a moment, by quick wit and a mental concentration of no mean order, combined with strict observance of the pettiest details, I ferreted out what bade fair to become a great diamond mystery; and when I say that this cigar end proves certain things to my mind, it does not become you to doubt the value of my conclusions.”

“Hear! hear!” cried Raleigh, growing tumultuous with enthusiasm.

“Your name? your name?” came from all parts of the wharf.

The stranger, putting his hand into the folds of his coat, drew forth a bundle of business cards, which he tossed, as the prestidigitator tosses playing-cards, out among the audience, and on each of them was found printed the words: 

---------------------------
|    Sherlock Holmes,     |
|      detective.         |
|                         |
|  Ferreting done here.   |
|                         |
|    Plots for Sale.    |
---------------------------

“I think he made a mistake in not taking the L200 for the watch.  Such carelessness destroys my confidence in him,” said Shylock, who was the first to recover from the surprise of the revelation.