Tone is the character of a literary piece. It may be a method of expression, or it may be expressed by the structure and contents of the piece. A satire, naturally, has a satiric tone to it, whatever its content. The expressions and materials used add to the satiric nature of the piece in different ways. Tone may also be used for contexts and as contrasts. A comedy, for instance, might have a contrasting tone of a sad story within it.
Examples of Tone in Literature:
Oscar Wilde:Picture of Dorian Gray
Charles Dickens: David Copperfield
Allan Drury: Advise and Consent