As a detective, Sherlock Holmes has unusual powers of reasoning and deduction. There are many examples in this book. In The Speckled Band Holmes deduces that danger will comethrough a ventilator and down a bell rope. In The Five Orange Pips he deduces that the murderers are on a sailing ship and he finds the actual ship by reasoning from sailing dates. In The Crown of Diamonds, Holmes's powers of deduction lead him to the man who has the missing diamonds and to an understanding of the behaviour of the innocent son.