When Heathcliff returns to Wuthering Heights after several years away, he begins visiting the Lintons at Thrushcross Grange. Nelly compares Heathcliff to a beast prowling between the Heights and the Grange:
His visits were a continual nightmare to me [...] His abode at the Heights was an oppression past explaining. I felt that God had forsaken the stray sheep there to its own wicked wanderings, and an evil beast prowled between it and the fold, waiting his time to spring and destroy.
Nelly uses the metaphor of sheep and a wild beast to compare the relative situations of the Earnshaws, Lintons, and Heathcliff. The "stray sheep," then, is Hindley Earnshaw at Wuthering Heights, who has given himself over to "wicked wanderings" like excess drinking and gambling. Heathcliff, the "evil beast," is currently taking advantage of Hindley's gambling addiction, intending to become master of Wuthering Heights in due time. Meanwhile, he "prowls" between the Heights and the Grange, or the "fold," where Catherine and her sister-in-law, Isabella Linton, live in sheltered safety for now. In particular, Isabella has become naively attracted to Heathcliff, a crush that Heathcliff and Catherine openly mock. Yet it's obvious to Nelly that Heathcliff is plotting something, and her choice of words—"waiting his time to spring and destroy"—hints that Heathcliff especially designs to destroy the innocent sheep Isabella. The metaphor thus builds suspense and a sense of foreboding, as readers wonder what horrible thing Heathcliff is scheming.
At Hindley's funeral, Heathcliff cruelly tells Hindley's young son Hareton that he's now going to mistreat the orphaned boy, just as Hindley mistreated Heathcliff after Mr. Earnshaw died. Heathcliff uses the metaphor of a crooked tree to describe his plans:
[...] he had the hypocrisy to represent a mourner; and previous to following with Hareton, he lifted the unfortunate child on to the table and muttered, with peculiar gusto, ‘Now, my bonny lad, you are mine! And we’ll see if one tree won’t grow as crooked as another, with the same wind to twist it!’
The "crooked tree" refers to Heathcliff, and the twisting "wind" is the mistreatment Hindley doled out to young Heathcliff that, he implies, had a distorting effect on his character. Heathcliff now threatens to unleash the same "wind" on Hareton, the young (so far straight-growing and healthy) "tree." Basically, Heathcliff intends to avenge himself by perpetuating the abuse he experienced. The "peculiar gusto" with which he utters this threat shows how much he relishes the prospect, and the fact that he hypocritically pretends to be mourning Hindley (and that he threatens Hindley's son at the funeral) underline just how "crooked" Heathcliff really is.
The metaphor also evokes the weather-beaten landscape of Wuthering Heights. Recall that when Lockwood first visits the Heights, one of the first details he observes is the stunted look of trees relentlessly blasted by the wind. The imagery suggests that Wuthering Heights is cursed with cruel winds of various kinds—as befits a Gothic setting.
Nelly wonders aloud why Edgar Linton and Hindley Earnshaw—both loving husbands and fathers initially—took such different paths in life, presenting them as foils for each other.
[...] Hindley, with apparently the stronger head, has shown himself sadly the worse and the weaker man. When his ship struck, the captain abandoned his post; and the crew, instead of trying to save her, rushed into riot, and confusion, leaving no hope for their luckless vessel. Linton, on the contrary, displayed the true courage of a loyal and faithful soul: he trusted God; and God comforted him. One hoped, and the other despaired: they chose their own lots, and were righteously doomed to endure them.
Nelly describes Hindley as an outwardly more robust man, yet when his "ship struck"—a metaphor referring to tragedy, in this case the death of his wife—the "captain abandoned his post," and the "crew" allowed the ship to founder, seemingly referring to Hindley's reason and other faculties. Instead of standing up in the face of disaster, in other words, Hindley gave in to a life of drunken dissipation instead of making wiser choices—essentially letting tragedy shipwreck his existence.
On the other hand, Linton, seemingly a softer and weaker man, suffered a comparable tragedy when Catherine died, yet proved himself the stronger man—he simply kept living with courage and faith as best he could despite his grief. From Nelly's perspective, then, hope and faith in God are evidence of the kind of strength that really counts—not mere outward strength. Linton's strength throws Hindley's weakness and wasted life into sharp relief, and even suggests that a more "feminine" man like Linton can be stronger than a more conventionally masculine man who misuses his resources.
Note, finally, that Nelly uses "doomed" in a more archaic sense here—i.e. "fated" to endure something, not necessarily "cursed" to do so—and also suggests that each man's choices helped shape the "doom" that awaited him, not fate alone.
When Cathy Linton meets her cousin Hareton for the first time, she's horrified to think she could be related to such a rough young man who's clearly not a gentleman. But, using an agricultural metaphor, Nelly reflects that Hareton, for all his lack of cultivation, still has the makings of a gentleman.
Still, I thought I could detect in his physiognomy a mind owning better qualities than his father ever possessed. Good things lost amid a wilderness of weeds, to be sure, whose rankness far over-topped their neglected growth; yet notwithstanding, evidence of a wealthy soil that might yield luxuriant crops, under other and favourable circumstances.
"Physiognomy" was a pseudoscience—especially popular during the Victorian period—that held that studying a person's face could yield insights into their personality and character. Nelly doesn't get very deep into the idea here; she simply uses the expression to mean that when she looks at Hareton, she believes she sees raw potential that even Hareton's father, who was college-educated, never had.
Nelly expresses that potential in terms of the metaphor of overgrown weeds. These weeds have grown in such unattractive profusion that they've all but choked out Hareton's natural potential, yet she believes that if it weren't for rich "soil"—Hareton's inborn traits and capacities—those "good things" wouldn't be present at all. In fact, if Hareton had been properly nurtured, those strong roots would have yielded "luxuriant crops," or a gentleman. The metaphor of rank, untended weeds versus sturdy, thriving crops emphasizes the degree of neglect Hareton has suffered, underscoring the fact that he's basically been permitted to run wild, with no training, checks on his instincts, or encouragement of his good tendencies. Yet it's worth noting that, from Nelly's perspective, Hindley wasn't as naturally good, even though he did have the advantage of being brought up with the care and privileges expected for a young gentleman. It seems that neither nature nor nurture alone is sufficient to produce a "luxuriant crop."
This passage also subtly underscores that Nelly, who grew up with Hindley and Catherine and helped raise Hareton as a baby, knows an Earnshaw when she sees one—that's why she can spot the potential underneath Hareton's ragged, uncultivated exterior.
Nelly reflects on Cathy's 16th birthday, when she and Cathy were out walking on the moors. She uses imagery conveying youth, promise, joy, and goodness:
She bounded before me, and returned to my side, and was off again like a young greyhound; and, at first, I found plenty of entertainment in listening to the larks singing far and near; and enjoying the sweet, warm sunshine; and watching her, my pet, and my delight, with her golden ringlets flying loose behind, and her bright cheek, as soft and pure in its bloom as a wild rose, and her eyes radiant with cloudless pleasure. She was a happy creature, and an angel, in those days. It’s a pity she could not be content.
Nelly describes Cathy as a "young greyhound," with boundless energy, and remarks affectionately on the young woman's carefree, innocent radiance—the "bright," "wild rose" complexion and "cloudless" happiness in her eyes. The natural environment reflects Cathy's joy, too, with singing larks and pleasant sunshine. Yet this lively, fruitful, promising imagery also foreshadows the loss of Cathy's innocence and freedom. Cathy is fresh and jubilant on the open moor, but she will soon be trapped, stagnant, and bitter as Heathcliff's prisoner at Wuthering Heights.
Given Nelly's perspective, looking back on this memory as she recounts it to Lockwood, the happy day on the moors has a wistful undertone ("She was a happy creature, and an angel [...] It's a pity she could not be content"). Nelly knows that Cathy met Heathcliff and Hareton on the moors that same day, which spelled the beginning of the end of her sheltered happiness. She implies that Cathy's encounter with the men of Wuthering Heights precipitated a loss of her "angelic" innocence, and that it stirred a latent discontentment in her. Her lively curiosity, then, ends up being her downfall, as she starts visiting the Heights and being pulled out of the protective world of the Grange that has fostered her innocence thus far.
Talking to Nelly, Heathcliff is comparing Hindley's son Hareton with his own son Linton, using metaphors of gold and tin:
Don’t you think Hindley would be proud of his son, if he could see him? almost as proud as I am of mine—But there’s this difference, one is gold put to the use of paving stones; and the other is tin polished to ape a service of silver—Mine has nothing valuable about it; yet I shall have the merit of making it go as far as such poor stuff can go.
Heathcliff's metaphors of tarnished gold and polished tin reflect how little he cares about the young men, as he's only using them to get what he wants from each (that is, ultimately, revenge for his own fate in being denied Catherine).
Hareton is "gold," meaning he is attractive, comes from good stock, and has valuable potential, yet he is being used for mere "paving stones"—Heathcliff essentially walks all over him by denying him education and forcing him to occupy a servant's role, though he could easily aspire to something much better.
On the other hand, sickly, peevish Linton is "tin," yet he's polished up to look like silver—"poor stuff" passed off to be someone of much higher quality than he is naturally. As a father, Heathcliff's only interest in Linton is to use him to snag Linton's cousin Cathy as a wife so that, when Linton inevitably dies, Heathcliff can then inherit the Grange, making his vengeance complete.
Heathcliff's metallic metaphors reveal which young man is truly the more desirable one (Hareton); moreover, Hareton is to be desired for his natural traits (gold), while Linton's (tin) are artificial—connecting to the novel's theme of civilization versus nature. They also underscore the fact that Heathcliff sees other people as materials to be molded for his own nefarious uses.
As Heathcliff anticipates death and reunion with Catherine, he hyperbolically compares her to both a devil and "heaven."
In Chapter 29, Heathcliff tells Nelly how strongly he senses his beloved Catherine's spirit near him, yet he can't see her. This is such a torment for him that he calls Catherine a "devil" whose "tortures" are "infernal" (hellish):
I ought to have sweat blood then, from the anguish of my yearning, from the fervour of my supplications to have but one glimpse! I had not one. She showed herself, as she often was in life, a devil to me! And, since then, sometimes more, and sometimes less, I’ve been the sport of that intolerable torture! Infernal—keeping my nerves at such a stretch, that, if they had not resembled catgut, they would, long ago, have relaxed to the feebleness of Linton’s.
Catgut is tough string or cord that's made from dried animal intestines (like those of sheep, hogs, or cattle). Basically, Heathcliff's nerves are extremely strong, unlike his feeble son's. Even so, Catherine's teasing presence has kept Heathcliff's nerves intolerably taut for years. She is a "devil" because she has the ghostly power to toy with Heathcliff, letting him feel her closeness but not see or touch her, making him long for death and reunion with her.
While this is Heathcliff's typical hyperbole (he wouldn't literally sweat blood, for example), his comparison of Catherine to a "devil" and the sense of her nearness to "torture" shows how desperately and obsessively he still yearns for Catherine, some 18 years after her death. It also suggests that his passion for her is disturbingly tangled up with resentment and even hatred.
Later, in Chapter 34, Heathcliff gives Nelly directions regarding his funeral:
No minister need come; nor need anything be said over me—I tell you, I have nearly attained my heaven; and that of others is altogether unvalued, and uncoveted by me!
Nearing death, Heathcliff has almost attained "his heaven"—that is, Catherine. Though, as the previous passage shows, he's just as inclined to call her a devil. At the same time, Heathcliff shockingly says he doesn't need a Christian burial, implying that Catherine is all the blessing he'll require as he enters the afterlife. Essentially, then, Catherine is Heathcliff's deity, even if she takes a cruelly unattainable form while Heathcliff remains alive.
As Heathcliff anticipates death and reunion with Catherine, he hyperbolically compares her to both a devil and "heaven."
In Chapter 29, Heathcliff tells Nelly how strongly he senses his beloved Catherine's spirit near him, yet he can't see her. This is such a torment for him that he calls Catherine a "devil" whose "tortures" are "infernal" (hellish):
I ought to have sweat blood then, from the anguish of my yearning, from the fervour of my supplications to have but one glimpse! I had not one. She showed herself, as she often was in life, a devil to me! And, since then, sometimes more, and sometimes less, I’ve been the sport of that intolerable torture! Infernal—keeping my nerves at such a stretch, that, if they had not resembled catgut, they would, long ago, have relaxed to the feebleness of Linton’s.
Catgut is tough string or cord that's made from dried animal intestines (like those of sheep, hogs, or cattle). Basically, Heathcliff's nerves are extremely strong, unlike his feeble son's. Even so, Catherine's teasing presence has kept Heathcliff's nerves intolerably taut for years. She is a "devil" because she has the ghostly power to toy with Heathcliff, letting him feel her closeness but not see or touch her, making him long for death and reunion with her.
While this is Heathcliff's typical hyperbole (he wouldn't literally sweat blood, for example), his comparison of Catherine to a "devil" and the sense of her nearness to "torture" shows how desperately and obsessively he still yearns for Catherine, some 18 years after her death. It also suggests that his passion for her is disturbingly tangled up with resentment and even hatred.
Later, in Chapter 34, Heathcliff gives Nelly directions regarding his funeral:
No minister need come; nor need anything be said over me—I tell you, I have nearly attained my heaven; and that of others is altogether unvalued, and uncoveted by me!
Nearing death, Heathcliff has almost attained "his heaven"—that is, Catherine. Though, as the previous passage shows, he's just as inclined to call her a devil. At the same time, Heathcliff shockingly says he doesn't need a Christian burial, implying that Catherine is all the blessing he'll require as he enters the afterlife. Essentially, then, Catherine is Heathcliff's deity, even if she takes a cruelly unattainable form while Heathcliff remains alive.