“Excellent,” he said.  “I took the words right out of his mouth.  ’It was numbered 86507B!’ I cried, giving, of course, the number of my own watch.

“He gazed at me narrowly for a moment, and then he smiled.  ’You grow more marvellous at every step.  That was indeed the number.  Are you a demon?’

“‘No,’ I replied.  ‘Only something of a mind-reader.’

“Well, to be brief, the bargain was struck.  I was to look for a watch that I knew he hadn’t lost, and was to receive L200 if I found it.  It seemed to him to be a very good bargain, as, indeed, it was, from his point of view, feeling, as he did, that there never having been any such watch, it could not be recovered, and little suspecting that two could play at his little game of deception, and that under any circumstances I could foist a ten-shilling watch upon him for two hundred pounds.  This business concluded, he started to go.

“‘Won’t you have a little Scotch?’ I asked, as he started, feeling, with all that prospective profit in view, I could well afford the expense.  ’It is a stormy night.’

“‘Thanks, I will,’ said he, returning and seating himself by my table—­still, to my surprise, keeping his hat on.

“‘Let me take your hat,’ I said, little thinking that my courtesy would reveal the true state of affairs.  The mere mention of the word hat brought about a terrible change in my visitor; his knees trembled, his face grew ghastly, and he clutched the brim of his beaver until it cracked.  He then nervously removed it, and I noticed a dull red mark running about his forehead, just as there would be on the forehead of a man whose hat fitted too tightly; and that mark, gentlemen, had the undulating outline of nothing more nor less than a tiara, and on the apex of the uppermost extremity was a deep indentation about the size of a shilling, that could have been made only by some adamantine substance!  The mystery was solved!  The robber of the Duchess of Brokedale stood before me.”

A suppressed murmur of excitement went through the assembled spirits, and even Messrs. Hawkshaw and Le Coq were silent in the presence of such genius.

“My plan of action was immediately formulated.  The man was completely at my mercy.  He had stolen the tiara, and had it concealed in the lining of his hat.  I rose and locked the door.  My visitor sank with a groan into my chair.

“‘Why did you do that?’ he stammered, as I turned the key in the lock.

“‘To keep my Scotch whiskey from evaporating,’ I said, dryly.  ’Now, my lord,’ I added, ’it will pay your Grace to let me have your hat.  I know who you are.  You are the Duke of Brokedale.  The Duchess of Brokedale has lost a valuable tiara of diamonds, and you have not lost your watch.  Somebody has stolen the diamonds, and it may be that somewhere there is a Bunker who has lost such a watch as I have described.  The queer part of it all is,’ I continued, handing him the decanter, and taking a couple of loaded six-shooters out of my escritoire—­’the queer part of it all is that I have the watch and you have the tiara.  We’ll swap the swag.  Hand over the bauble, please.’