Read the final sentence of this chapter. Explain in your own words what it means. In what way is is his conversation with his brother also a message for his daughter?

But I never figured out how Atticus knew I was listening, and it was not until many years later that I realized he wanted me to hear every word he said.

Atticus' discussion with his brother served a dual purpose. It explained events to his brother, and it served as a lesson to his daughter. Atticus understands that Scout might not understand his words, but he hopes they make her think, and if she has questions..... he wants her to come to him.