Now that the important murders have been committed by Macbeth, the word night starts to take a different in its usage and meaning. Though it maintains its meaning as to signify impending doom and negativity, the target of that doom and badness is now directed at Macbeth. Starting with Scene 1, the witches cast a spell in their cauldron to create apparitions that would deceive Macbeth. Though the usage of night in each separate quote has nothing of importance, in big picture, it is part of a spell to bring Macbeth down. Also, now that the impending doom and negativity is directed at Macbeth, Macbeth barely makes use of the word night in Act 4. However, the users of the word night are now those who have been affected negatively by Macbeth.