This enables the writer to include elements in the story from other places (India, the Andaman Islands) and from the time before this story begins.

The description of the setting is used to reflect the mood or events in the novella, particularly when the weather is dark and dismal.

Similes and metaphors are used by the writer to create a sense of place or character.

Direct speech is used to convey to the reader the attitudes and values of each character.

As the story is told through the voice of Dr Watson, the reader is able to experience the action and emotions of the narrator first-hand.