The novel's mood varies between nostalgic, melancholy, morbid, dramatic, and hopeful, shifting alongside the various conflicts that crop up throughout the narrative.
A nostalgic, melancholy mood prevails as Margaret must say goodbye to her beloved home of Helstone and move to a dreary, unfamiliar city lacking in natural beauty. The novel's emphasis on Milton's smoky, gray surroundings, compared to the green freshness Margaret remembers in Helstone, enhances this mood. A morbid note becomes increasingly common as Margaret watches a succession of loved ones and neighbors sicken and die, usually because of the unhealthy and oppressive environment in Milton.
A dramatic mood marks Margaret's evolving relationship with Thornton, as she resists aspects of his manufacturing perspective and frets over Thornton's mistaken impressions about her (and as Thornton wrestles with his unrequited attraction to her). This mood helps readers grasp the stakes of class antagonism in Milton and also adds tension to the relationship between the two main characters—readers wonder if their perspectives can ever be reconciled and, more pedestrianly, whether they'll ever like each other.
Finally, the mood is increasingly tinged with hope as Margaret moves away from Milton-Northern and matures into a more adult perspective. This tempers the earlier melodramatic mood, as Margaret becomes less nostalgic about Helstone, less judgmental of Thornton, and more inclined to see both the strengths and weaknesses of people, places, and systems.
