foreshadow

"This writing, however, was nothing but a name repeated in all kinds of characters-large and small-Catherine Earnshaw, here and there varied to Catherine Heathcliff, and then again to Catherine Linton."  This line was said in the first half of the book.  However, it helps when talking about the chronological order of the novel.  At this part, Lockwood finds these names written on a wall.  This foreshadows Nelly telling the story of Wuthering Heights.  This part at the beginnings prepares the reader to know that either Catherine gets married three times, or she has some important relation to all them in some way.  Later in the story, they explain that Catherine and Heathcliff once loved each other.  She was an Earnshaw, and she married a Linton.  This foreshadowing helps with the order of the story.