The author had Mr Woodhouse refer to Frank Churchill as Mr Weston's "natural son." I can only assume that the author had no idea what the term means, else she would never have Mr Woodhouse cast any aspersions on a young gentleman's birth. (For those who don't know the book, the young man in question is the child of Mr Weston's first marriage, and was adopted and raised by his late mother's brother and sister-in-law. This is, in fact, a plot element in Emma, and common knowledge among all the characters. Mrs Churchill had a great deal of control over Frank's life.)
It's now impossible for me to read further.