In what ways does Miller use irony in The Crucible to manipulate the audience's sympathies?

Irony appears in several places in this play.  First of all, there is the irony that the girls are the ones guilty of witchcraft, but they are accusing everyone else.  The audience immediately feels guilty for their victims.  John Proctor, when trying to recite the ten commandments, accidentally omits the one about adultery.  Elizabeth has to remind him of it causing the audience to see and feel her pain.  Francis Nurse and Giles Corey provide evidence of their wives' innocence yet they are taken into custody.  And finally, at the end, the audience feels for John Proctor because to prove his innocence and his goodness, he is forced to make the decision to not confess and die.