It is a classic horror device to use the darkness of night to create suspense. Interestingly, in the Globe Theater of Shakespeare's day, the play would have been performed in full daylight (approx. 3pm) and so, there would have been no opportunity for the audience to experience this mood-setting nighttime scene except through the actors use of text and props (like torches to indicate that it is dark) and their own imaginations.
That said, Shakespeare makes sure to exploit some devices that we commonly associate with "things that go bump in the night" to assist in the overall foreboding and suspenseful atmopshere of this "nocturnal setting:"
- Banquo and Fleance discuss that the hour is past midnight, a sure indication that danger/evil is afoot.
- Banquo speaks to Fleance of a premonition ("A heavy summons lies like lead upon me") and also of his bad dreams ("cursed thoughts that nature/Gives way to in repose.")
- Upon Macbeth's entrance, a jumpy Banquo asks for his sword and calls out, "Who's there?"
- Macbeth, once he is alone onstage in darkness, can't decide if a dagger really floats before him, or if his imagination has put it there.
- Macbeth uses 7 lines of his soliloquy to create a suspenseful sense of the time and place:
. . . Now o'er the one half-world
Nature seems dead, and wicked dreams abuse
The curtain'd sleep. Witchcraft celebrates
Pale Hecate's offerings, and wither'd murder,
Alarum'd by his sentinel, the wolf,
Whose howl's his watch, thus with his stealthy pace,
. . .Moves like a ghost.
- A bell breaks the silence to toll the hour that Macbeth must go and commit the murder, a creepy sound in the dead of night.
There are indications of dramatic enhancements to this scene -- the men whispering by torchlight, the surprise entrance of Macbeth, the potential sound effects of the bell and wolf's howl -- and yet it is the text itself that Shakespeare mainly relies upon to create the suspense and foreboding of this late night scene, a suspense that relies heavily upon the audience's imaginations.
For more on Act II, scene i and Macbeth's famous dagger soliloquy, please follow the links below.