What effect does Miller intend to produce when creating the setting for 'The Crucible?'

In  Act two it opens in the house of John and Elizabeth Proctor, eight days later. The room is very long with a low ceiling. It is quit dark in the room. The space is quit enclosed.  They begin having dinner in there common room and it comes out that Mary Warren has gone into Salem.  John Proctor had forbidden her to go to Salem and had ago at his wife for allowing Mary to override her.  She tells John what Mary has told her about the meet of a court and its actions about the girls' accusations.  They argue again about his past involvement with the girl and Elizabeth's continuing doubt.  Mary Waren arrives home at that moment and so Proctor turns his anger onto her.  She hangs limp and claims illness.  Proctor releases her and reminds her of her duty to his family. 

In act 3 Martha Corey is on trial in the Salem court.  Her husband bursts into the courtroom shouting that he has evidence of her innocence  Francis Nurse was with him.  They reveal that Elizabeth Proctor has claimed to be pregnant and when Proctor still refuses to drop his charges of fraud (His wife cannot be hung as long as she carries an  child), Danforth insists that he means to attack them.  Proctor speaks up at this point and compels Mary Warren to admit to her involvement in Abigail's game.  Abigail denies Mary's charges and stands by What she said.  Proctor continues to try to shame Abigail and when it looks like he is going to succeed, Abigail unleashes her strongest weapon.  She begins to act as though she is afflicted, and is quickly followed by the other girls.  Proctor, having no options left, reveals his affair with Abigail.  Proctor and Abigail are instructed to turn their backs as Elizabeth Proctor is brought in.  They ask her if her husband has been unfaithful.  Not knowing that he has confessed and thinking of his protection, she denies it.  Abigail and the other girls continue to act as though afflicted by Mary Warren until the girl finally cracks. Proctor and Giles Corey are led off to the prison. 

The final act opens in the Salem jail.  Several hangings are planned for that morning, including the hangings of John Proctor and Rebecca Nurse.  Danforth and Hathorne arrive. They discuss how Parris has seemed rather unstable lately.  When he enters, they discover that Hale has been trying to convince Rebecca Nurse to save herself by confesing. They ask Parris why he has been troubled and it is revealed that Abigail has gone with Mercy Lewis.  Parris attempt s to convince the men to stop the hangings, realizing that it has all been taken to far.  The men refuse however, to even delay the hangings.  They then speak to Elizabeth Proctor, now three months pregnant, to try to convince her to compel her husband into confessing and saving himself.  She promises nothing but asks to speak to him anyway.  When She tells him that Giles Corey was presssed to death.   The court piled stones upon him, the idea being that he would answer under the stress of the gret weight.  Instead, Corey simply called for more weight until he was finally crushed .   Hathorne enters and John tells him that that he will keep his life.  The men enter and begin to take his confession.  He finally sign it but then, unable to stand the lie, rips the confession to shreds.  Danforth announces his fate.  Rebecca and John are led out.  Hale begs Elizabeth to plead with her husband but she will not.