How did Jane try to compose her nerves?

In Chapter 15 of Jane Eyre, Rochester reveals to Jane some of the murkier aspects of his past. He tells her that Adele—the girl for whom Jane has been acting as a governess—is the daughter of a Frenchwoman called Celine. Years before, Rochester had had an affair with Celine. After he caught her cheating on him, he ended the relationship, but not before shooting and injuring her lover in a duel. Rochester doesn't think that Adele is his daughter, but he felt sorry for her anyway, not least because her mother had abandoned her, so he took her back to England with him.
As she tosses and turns in bed that night, Jane can't stop thinking about Rochester's scandalous story. She feels agitated and unnerved, her anxiety made worse by a sudden sound at her bedroom door. Jane quickly reassures herself that it's most probably Pilot, Mr. Rochester's Newfoundland dog. Silence returns to the house and settles Jane's fraught nerves. Now she feels herself gently falling into a deep slumber once more. But it doesn't last for very long; soon Jane will be disturbed once again, this time by a fire.