What is it that Jem is trying to get Atticus to understand in Chapter 8 of To Kill a Mockingbird?When Scout comes home with the mysterious blanket...

Jem figured out what Atticus' little grin and roundabout
hints were about before Scout caught on (in Chapter 8). When Atticus suggested that they
get some wrapping paper in which to return the mysterious blanket, Jem suddenly "seemed
to have lost his mind." He spilled all the little secrets the children had kept to
themselves about Boo Radley--including the knothole and the lost pants. Jem understood
what Atticus did not spell out clearly--that it was Boo who had placed the blanket
around Scout's shoulders. Why he suddenly blurted out the children's secrets is another
matter, but it must have been a combination of his own guilt and his recent realization
that Boo was really a good guy that caused him to be so talkative. He settled down
quickly enough to rattle Scout a bit before promising Atticus that he had no desire to
"do anything" to Boo again.