"Very," said Holmes. "Business is getting by slow degrees to be an exact science. It reminds me of the Brighton mystery, in which I played a modest part some ten years ago, when I first took up ferreting as a profession. I was sitting one night in my room at one of the Brighton hotels, which shall be nameless. I never give the name of any of the hotels at which I stop, because it might give offence to the proprietors of other hotels, with the result that my books would be excluded from sale therein. Suffice it to say that I was spending an early summer Sunday at Brighton with my friend Watson. We had dined well, and were enjoying our evening smoke together upon a small balcony overlooking the water, when there came a timid knock on the door of my room. "'Watson,' said I, 'here comes some one for advice. Do you wish to wager a small bottle upon it?' "'Yes,' he answered, with a smile. 'I am thirsty and I'd like a small bottle; and while I do not expect to win, I'll take the bet. I should like to know, though, how you know.' "'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?'