How does the closer friendship between Lyddie and Brigid affect Lyddie?

Lyddie's friendship with Brigid is an important step in Lyddie's growth as a person. At first Lyddie has no time for Brigid and only views her as an interruption, someone who will prevent her from earning as much money as possible by being highly productive with her looms. She also dislikes Brigid because Brigid is Irish; she dresses, smells, and talks funny. But when Lyddie comes down with a life-threatening fever, Brigid helps nurse her back to health. After that, Lyddie takes more interest in Brigid, becoming her mentor. She teaches Brigid to read, beginning with her ABCs. She meets Brigid after work and on Sundays to continue helping her. Lyddie is learning to be a giver to others; she is now mentoring Brigid the way Diana once mentored her. When Lyddie's roommates and Diana have all left the Concord Corporation, Lyddie is glad to have Brigid as a friend, and she is learning the value of friendship in a way she didn't understand when she had her roommates and Diana with her. 

Because Lyddie and Brigid normally walk out of the factory together, Lyddie notices Brigid's absence on the night when Mr. Marsden tries to take advantage of her. Lyddie goes back into the factory and hears Brigid pleading with the overseer. Lyddie's protective nature is aroused, just as it was when a bear threatened her family at the beginning of the novel. She grabs a water bucket and jams it down over the overseer's head, and she and Brigid run away. This brave action on Lyddie's part has negative consequences for her. Mr. Marsden retaliates by having her fired for "moral turpitude." Before leaving town, Lyddie buys Brigid a book and delivers it to her. She also writes letters to Mr. Marsden and Mrs. Marsden, putting a further protection in place to make sure the overseer does not try to violate Brigid again. Although Lyddie gets fired from the factory, it opens her up to the possibility of attending college. Her willingness to sacrifice her own position for Brigid turns out to be an important step on Lyddie's path to being an independent woman.