The Adventure of the Burglar's Code

As Sherlock Holmes and I returned from the concert hall, where we had heard the incomparable Joseph Joachim playing Mendelssohn's magnificent violin concerto, Holmes' attention was drawn to the doorway of 221B Baker Street as we approached home.

'Halloa, what's this?' said Holmes.

At the bottom of the door a small X had been drawn in chalk.

'Watson, dear fellow, you wouldn't happen to have your revolver with you, would you?' asked Holmes. When I answered in the negative, Holmes shrugged, saying, 'It's of no consequence, anyway, the deed hasn't happened yet, or Mrs. Hudson and the household would be aroused and in alarum. Stay here a moment, Watson, there's a good fellow.'

Holmes went quickly into the house and returned a few minutes later with a stick of chalk and a piece of cloth. He rubbed out the X with the cloth, and in its place, carefully marked a capital letter D. 'There, that should ensure our safety, for the moment at least, until I can get some of the Baker Street Irregulars to watch the house for a few days. Still, it would be wise to keep your army revolver handy, Watson, just in case.'

'Just in case what, Holmes? I am baffled, what are these chalk marks and why are they of significance?'

'They are burglar's signs, Watson,' replied Holmes. 'Thieves use these signs to identify houses to members of their gang. I myself have made a study of these signs, and have even written a monograph on the subject. The letter X, or cross sign, indicates a house ripe for plucking; the letter D, which I scribed onto our door, indicates a house too dangerous to enter. It should keep us safe until arrangements can be made.'

'Good Heavens, Holmes, quite extraordinary!' said I.

'Commonplace, Doctor,' he answered. 'Do let us go upstairs, I am anxious to reproduce some of the Mendelssohn on my Stradivarius. It will sound sweeter than that Cuyper fiddle that Joachim was playing tonight, I think.'

burglar's code.