What effect does the setting of the opening scene have in the play macbeth?

The opening scene of the play introduces the theme of the play and lets the audience know what to expect.  In this scene, the three Weird Sisters are conjuring.  Immediately they let the audience know that they will appear again in the play. ("When shall we three meet again""There to meet with Macbeth").

first of all the mood needs to be defined: it is obviously a mood of deceitful relief and serenity. why? because the cape horn is one of the most violent maritime regions of earth and although it has been left behind, it is a personification of ahab’s delirium and the fact that the end of the passage speaks about it about being “hidden” but “raving” immediately conveys the feeling the calm is not permanent but fleeting.

furthermore, the oxymoron “mild stun'sails” is the first instance of such feeling as the adjective “mild” is associated with “stunned” underscoring the fleeting nature of this “tranquil” moment. and the contrasts keep piling up, with the opposition between “dark den” and “blessed light and air” to end with the final conclusion that leaves the reader with the uneasy knowledge that this is just a reprieve.

the narrator is a first person, participant one, who describes in the simple past tense important and difficult events in his earlier life. he also provides temporal markers as the month (january) and the time (12: 30 pm). finally the account of his experience is very detailed, to the extent that a participant narrator would talk the same way about his experiences. a good example of such detail is the mention of the “bovril ration” which historically was a native american food adopted by european explorers in arctic and antarctic regions due to its high level of calories.