What do we learn about Uncle Jack in To Kill a Mockingbird?
In Chapter 9, Scout mentions that every Christmas Uncle Jack Finch comes to visit and stays a week along with Aunt Alexandra and her grandson Francis, whom she finds tiresome. This year Uncle Jack has two long packages for his nephew and his niece. Scout remarks that she finds her uncle a bit odd:
Jem and I always thought it funny when Uncle Jack pecked Atticus on the cheek; they were the only two men we ever saw kiss each other.
But, Scout adds that he is one of a few men of science who do not frighten her because Uncle Jack does not act like a doctor. As proof, she relates the time that she had a splinter in her foot, but Uncle Jack had her laughing so hard that she did not feel him pull it out.
Uncle Jack is a confirmed bachelor; the "only woman [he] can stand" is his cat Rose Aylmer. Later, when Scout uses some expletives of which Jack does not approve, he chastises her after dinner as she sits upon his knee. But, he learns from Scout that "bad things" are being said about Atticus, and Francis is one of those participating. Later, Scout overhears Uncle Jack asking Atticus about the case.