Anton Chekhov, the great Russian playwright, reportedly said that "If in Act 1 you have a Pistol hanging on the Wall, then it must fire in the last act." This is a plot device which occurs several times in All My Sons. Describe two of these occasions.
Hello! You asked about All My Sons and Chekhov's Gun. This is a literary device where Chekhov tells writers that they must bring to pass what they promise and that everything must happen for a reason in a story. Quite simply, if there is a loaded gun in a preceding chapter, there must be a corresponding action where the gun goes off in a later chapter.
You asked about two instances where this happens in All My Sons by Arthur Miller.
1) In Act I, Larry's tree blows over in the backyard in a storm. Larry's mother, Kate, chastises her husband, Joe, for planting the tree; she claims that Larry isn't really dead and they have rushed to judgment. She says that the fallen tree is appropriate; after all, Larry isn't dead. However, the falling of the tree is a "foreshadowing" of real evidence presented in Act III, when Ann shows Larry's suicide note to Kate. In it, Larry states that he knows his father is guilty and that he plans to crash his own plane to atone for his father's guilt. So, the "loaded gun" here is the fallen tree in Act 1. In Act III, the bullet hits its target; Larry really is dead. His letter proves it.
2) In Act II, we see "foreshadowing" that Joe might actually be guilty for approving the shipment of the cracked cylinder heads; Kate slips when she tells George, Ann's brother, that Joe hasn't been sick in fifteen years. We learn that this is Joe's alibi for claiming himself innocent of all wrong-doing on that day, that he had the flu. Eventually, the truth is outed by Kate herself. She knows about Joe's part in the decision to ship out faulty cylinder heads (twenty-one pilots are killed as a result) but can't quite bring herself to think that her own husband is responsible for the death of their son, Larry. So, the "loaded gun" here is Joe's guilt. His guilt is proven in Act II when he admits that he made a business decision for the sake of his family on that fateful day. So, what will Joe do now, the reader asks? The bullet hits its target, quite literally, in Act III when Joe commits suicide by shooting himself.
Hope this helps. Thanks for the question!