What are some figurative devices used in Act 4 of Shakespeare's Romeo and Juliet?
In Act 4 of Romeo and Juliet, Shakespeare uses personification, a type of figurative or literary device in which a non-living object is given human qualities. For example, Juliet says to Friar Laurence in scene 1, "this bloody knife/Shall play the umpire." In this figure of speech, a knife is likened to an umpire who can choose between the two difficult choices Juliet has to make--whether to marry Paris or admit she is already married to Romeo. Later in the scene, the Friar says, "No warmth, no breath, shall testify thou livest," meaning that no breath will give away that Juliet is still living after she's taken the drug he prescribes. This is another example of personification. At the end of scene 3, Juliet summons the vial with the drugs she is taking as if it is human. She says, "Come, vial," and she addresses the vial like it is a person.
Juliet uses similes later in scene 3. She says that in the tomb, she might hear screams that she describes as "shrieks like mandrakes torn out of the earth." Mandrakes are a type of root that was rumored to yell like a human when torn from the earth. Mandrakes were thought to have had magical qualities that were used in witchcraft. In scene 5, Romeo uses a metaphor to compare money to poison. When he uses money to buy poison from the apothecary, he says, "gold, worse poison to men’s souls" than the poisons the apothecary sells.
Early in the first scene, Paris uses an allusion to the Roman goddess of love, Venus. He says that "Venus smiles not in a house of tears" (4.1.8). He hopes to marry Juliet soon, but she seems to cry over the death of her cousin, Tybalt (though she is really weeping over the exile of her new husband, Romeo). When Paris alludes to Venus in this way, he means that it is hard for love to grow in a home filled with such sadness. Paris has not been able to pursue his feelings for Juliet lately because of her terrible grief.
Later, when Juliet speaks to Friar Lawrence in desperation because she will be forced to marry Paris, she says, "God joined my heart and Romeo's" (4.1.56). She is speaking of the heart as though it were the actual physical site in which love takes place, but it is not. Here, she is using a figure of speech called metonymy. Metonymy occurs when one substitutes something associated with a thing for that thing. She does not say that God made them each love one another; she says that God joined their hearts, substituting hearts for love because hearts are associated with love. It is a more poetic way to say the same thing.