Francis reveals that Aunt Alexandra is racist and considers Atticus the ruination of the family.
Scout finds Francis boring, and has never liked him, but she gets even more annoyed when she realizes that he is insulting her father.
Talking to Francis gave me the sensation of settling slowly to the bottom of the ocean. He was the most boring child I ever met. (ch 9)
Francis is more than just boring though. He intentionally goads Scout, telling her what Aunt Alexandra (his grandmother) said about her father.
Grandma says it's bad enough he lets you all run wild, but now he's turned out a nigger-lover we'll never be able to walk the streets of Maycomb agin. He's ruinin' the family, that's what he's doin'." (ch 9)
Scout is very upset by this. It is one thing when the whole town seems to be against her, but now her family has turned on her. She feels frustrated and confused, and she lashes out. Francis tattles, and Uncle Jack spanks Scout. When she tells him what really happened, he is upset—but she asks him to drop it.
This incident demonstrates that Aunt Alexandra’s problems with Atticus move beyond just wishing Scout wore frilly dresses. Clearly, she wishes that Atticus was raising his children to consider themselves better than others.
In chapter nine of To Kill a Mockingbird, Atticus's brother, Uncle Jack, comes to stay with the Finch family for Christmas. The family goes to visit Uncle Jimmy, Aunt Alexandra (Atticus's sister), and cousin Francis at the Landing. Francis proves to be an immediate nuisance, and Scout considers him to be "the most boring child [she] ever met." He is a tattletale who reports back to Aunt Alexandra, who in turn nags Atticus about his parenting abilities.
At the dinner table, Francis irritates Scout by teasing her about Dill, who he refers to as a "little runt," and tells Scout that she is "mighty dumb sometimes." He then reveals the startling attitude of Aunt Alexandra, stating:
If Uncle Atticus lets you run around with stray dogs, that's his own business, like Grandma says, so it ain't your fault. I guess it ain't your fault if Uncle Atticus is a nigger-lover besides, but I'm here to tell you it certainly does mortify the rest of the family--
This revelation--that Aunt Alexandra is judgmental enough to refer to Atticus in such a way--is deeply disturbing to Scout. Scout goes on the offensive, attacking Francis and chasing him off into the kitchen, eventually splitting her "knuckle to the bone on his front teeth." Unfortunately for her, Uncle Jack intervenes quickly and punishes Scout with a "licking."