The novel
At the time the novel was written, capitalism and the Industrial Revolution were the mainstay of the British economy.
Cash became more important than land, so many of the middle class had more economic power than those of the upper class.
Relationships between the classes are a part of the novel with each group featured:
Hareton - farming class
Lintons - the gentry
Heathcliff - rich capitalist
The new wealthy capitalist wanted the same standing as traditional gentlemen and two marriages in the novel are possible because of these changes in class and status.
Ending
Lockwood grows tired of the moors and moves away. Eight months later he sees Nelly again and she reports that Cathy has been teaching the still-uneducated Hareton to read. Heathcliff was seeing visions of the dead Catherine; he avoided the young people, saying that he could not bear to see Catherine's eyes, which they both shared, looking at him. He had stopped eating, and some days later was found dead in Catherine's old room.
In the present, Lockwood learns that Cathy and Hareton plan to marry and move to the Grange. Nelly says that the locals have seen the ghosts of Catherine and Heathcliff wandering abroad together, and hopes they are at peace.
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