In A Separate Peace what is the "joke" Finny understands in chapters 7 and 8?
When Brinker Hadley enters Gene's room, he sarcastically remarks that Gene has "real influence" around the campus of Devon. After all, he has a big room to himself now that Finny has been injured.
"I'll bet you knew all the time Finny wouldn't be back this fall. That's why you picked him for a roommate, right...
"You fixed it,....You knew all the time. I'll be it was all your doing."
Ill at ease, Gene tries to dismiss these remarks, by retorting, "what a crazy thing to say," but his voice is strained. So, he suggests that he and Brinker go to the butt room. Once there, Brinker introduces Gene as they enter, "Here's your prisoner, gentlemen." When one of the boys queries, "What's the charge?" Brinker responds,
"Doning away with his roommate so he could have a whole room to himself. Rankest treachery....Practically fratricide."
Gene shakes him off,
"Shut up! I swear you ride a joke longer than anybody I know."
Surprisingly, however, Finny does return to Devon, just showing up one night before Gener returns to the dormitory room. In the morning, Brinker barges into the room to ask Gene if he is ready to sign up for the war only to also discover Finny's presence. "Your little plot didn't work so well after all," he comments. Of course, Finny demands to know the meaning of Brinker's remark.
The room was bitterly cold. I stood trembling in front of Phineas, still holding his crutches in place, unable to turn and face Brinker and this joke he had gotten into his head, this catastophic joke.
After Brinker's words, Finny looks at Gene with an "odd expression." Evidently, he has deduced the meaning of Brinker's innuendos.