Complex sentence: The prominence given to the topics of mesmerism and clairvoyance heightened the general disapproval of the book, which outraged literary London with its mesmeric evolutionary atheism, causing a lasting division between Harriet Martineau and some of her friends.
Split into simpler sentences: The prominence given to the topics of mesmerism and clairvoyance heightened the general disapproval of the book. Literary London was outraged by its mesmeric evolutionary atheism, and the book caused a lasting division between Martineau and some of her friends.