"Fatherly" Moriarty (Dramatic Irony)
When Inspector MacDonald is speaking with Holmes of his interview with Professor Moriarty, he says that when the professor put his hand on his shoulder before leaving “it was like a father’s blessing before you go out into the cruel, cruel, world” (173) This is ironic because, given that MacDonald is a policeman, Moriarty no doubt holds nothing but hatred for the man; also, given Moriarty’s deeds, it is likely that he has greatly contributed to the evil in MacDonald’s “cruel, cruel world.”
The missing dumb-bell (Dramatic Irony)
Many times in Sherlock Holmes stories, Holmes’ advice is sought in a matter because there is a total absence of clues. In this case, the police find themselves overrun with clues that all seem equally important: bloody footprints, the unusual weapon, a card inscribed 'V.V.' next to the body, the peculiar burn on the dead man’s arm, etc. The one observation that Holmes makes that seems to be of no consequence whatsoever is that there is only one dumbbell in the room. This oddity is generally looked on as unimportant by the other detectives, but, as it turns out, it is the most revealing clue. As Holmes says later, “Dear me, Watson, is it possible that you have not penetrated the fact that the case hangs upon the missing dumb-bell?” (213.)
The Scowrers' love of music (Situational Irony)
The Scowrers are described as a brutal and heartless gang of murderers, who take pride in their bloody work with a total absence of shame. Yet when describing one of their meetings, the reader finds that “the tender or pathetic in music could move them to tears” (274) This well placed irony makes the men even more twisted and vile in the eyes of the reader. The Scowrers have sympathy and feeling for the fictional characters in songs, but not for the lives of their victims.
Douglas' demise (Dramatic Irony)
John Douglas, otherwise known as either Jack McMurdo or Birdy Edwards, escapes death multiple times. Indeed, at the beginning of the story we believe he is dead. We learn that the Scowrers of Vermissa Valley hunted him for years before finally catching up with him. It is only after he has shaken them off, apparently safe for the first time in years, that he ends up meeting his demise at the hands of Professor Moriarty. This piece of cruel irony provides a poignant ending to the novel, and also intensifies the odious persona of Holmes’ nemesis, Moriarty.
