What does Ella learn about Hattie's hair from her magic book?

After being told to end her friendship with Areida, Ella spends time looking at her magic book so that she can put off seeing Areida and hurting her feelings. The book shows her letters that various people have written, including a letter from Dame Olga to Hattie in which she learns that there is something strange about Hattie's hair. Ella realizes that Dame Olga and Hattie must wear wigs which explains their beautiful hair.