“‘It is quite simple,’ said I.  ’The timidity of the knock shows that my visitor is one of two classes of persons—­an autograph-hunter or a client, one of the two.  You see I give you a chance to win.  It may be an autograph-hunter, but I think it is a client.  If it were a creditor, he would knock boldly, even ostentatiously; if it were the maid, she would not knock at all; if it were the hall-boy, he would not come until I had rung five times for him.  None of these things has occurred; the knock is the half-hearted knock which betokens either that the person who knocked is in trouble, or is uncertain as to his reception.  I am willing, however, considering the heat and my desire to quench my thirst, to wager that it is a client.’

“‘Done,’ said Watson; and I immediately remarked, ‘Come in.’

“The door opened, and a man of about thirty-five years of age, in a bathing-suit, entered the room, and I saw at a glance what had happened.

“‘Your name is Burgess,’ I said.  ’You came here from London this morning, expecting to return to-night.  You brought no luggage with you.  After luncheon you went in bathing.  You had machine No. 35, and when you came out of the water you found that No. 35 had disappeared, with your clothes and the silver watch your uncle gave you on the day you succeeded to his business.’

“Of course, gentlemen,” observed the detective, with a smile at Sir Walter and Hamlet—­“of course the man fairly gasped, and I continued:  ’You have been lying face downward in the sand ever since, waiting for nightfall, so that you could come to me for assistance, not considering it good form to make an afternoon call upon a stranger at his hotel, clad in a bathing-suit.  Am I correct?’

“‘Sir,’ he replied, with a look of wonder, ’you have narrated my story exactly as it happened, and I find I have made no mistake in coming to you.  Would you mind telling me what is your course of reasoning?’

“‘It is plain as day,’ said I.  ’I am the person with the red beard with whom you came down third class from London this morning, and you told me your name was Burgess and that you were a butcher.  When you looked to see the time, I remarked upon the oddness of your watch, which led to your telling me that it was the gift of your uncle.’

“‘True,’ said Burgess, ‘but I did not tell you I had no luggage.’

“‘No,’ said I, ’but that you hadn’t is plain; for if you had brought any other clothing besides that you had on with you, you would have put it on to come here.  That you have been robbed I deduce also from your costume.’

“‘But the number of the machine?’ asked Watson.

“‘Is on the tag on the key hanging about his neck,’ said I.

“‘One more question,’ queried Burgess.  ’How do you know I have been lying face downward on the beach ever since?’

“‘By the sand in your eyebrows,’ I replied; and Watson ordered up the small bottle.”