The Adventure of the Engineer’s Thumb

⁠​​​‌​​​​‌‌​​​​‌​‌​​‌​‌‌​‌​​‌​‌​‌​​​​‌‌‌​​​‌‌‌‌​‌​​​‌‌​​​‌​​‌‌​​‌⁠Of all the problems which have been submitted to my friend, Mr. Sherlock Holmes, for solution during the years of our intimacy, there were only two which I was the means of introducing to his notice—that of Mr. Hatherley’s thumb, and that of Colonel Warburton’s madness. Of these the latter may have afforded a finer field for an acute and original observer, but the other was so strange in its incep