The narrator uses a simile that is laden with verbal irony to introduce the character of Blanche Ingram in Chapter 17:
Blanche and Mary were of equal stature – straight and tall as poplars. Mary was too slim for her height, but Blanche was moulded like a Dian.
Jane idealizes Blanche's image by comparing her to a statue of Diana and a poplar tree. Diana, the Greco-Roman goddess, represents perfect, desirable femininity. The poplar tree is native to northern climates, including England. Poplar flowers fruit into fluffy white orbs that look like cotton balls all over the tree. Jane is imagining Blanche as a symbol of white, English femininity. Blanche's very name means "white," which on the surface contrasts with Bertha's association with Blackness. It certainly contrasts with the gothic darkness of Thornfield.
Blanche's name and the narrator's language here are ironic because Blanche in fact represents further enmeshment in England's colonial economy. Although Jane and the reader don't yet know the extent of the problem, the darkness of Thornfield is an effect of its colonial entanglement. (The novel operates on racist ideology that maps sin and corruption onto darkness and Blackness.) As a fashionable woman, Blanche consumes many products that are connected with slavery and colonialism. This kind of unethical consumerism had long been held against wealthy women, and the novel holds it against Blanche. Jane, who is not in the class of women who can afford luxury imports, finds Blanche shallow and materialistic. Her name and her description as a poplar or a Diana do not match her substance, which is implicated in all of England's problems. As the novel demonstrates by the end, it is not Blanche who stands to "whiten" Rochester's soul by marrying him, but rather Jane.
In Chapter 23, Mr. Rochester tells Jane that he is going to marry Blanche Ingram and that he has arranged a governess position for Jane in Ireland. When she gets upset with him, he says she should stay at Thornfield, kisses her, and attempts to subdue her with a simile:
‘Jane, be still; don’t struggle so, like a wild frantic bird that is rending its own plumage in its desperation.’
‘I am no bird; and no net ensnares me; I am a free human being with an independent will, which I now exert to leave you.’
Rochester can't make up his mind about whether Jane should stay at Thornfield or leave. As soon as Jane decides to cut her losses by taking up the governess position, Rochester decides he won't let go of her. By comparing Jane to a bird that is destroying its own feathers in a futile attempt to escape, Mr. Rochester frames her attempt to leave him as self-sabotage. Jane sees through his manipulative accusation that she is being too emotional. She resists the simile, asserting to Mr. Rochester that she is no scared animal caught in a human man's trap. Rather, she is just as human as he is. Her will has equal weight to his, and she is going to use it to walk away.
There is an underlying metaphor here: whereas Jane can manage to get away, Bertha remains caught in Mr. Rochester's net. She is the real "wild frantic bird." Jane and the reader do not yet know about Bertha's existence, but Jane has noticed the signs of her "desperation." Mr. Rochester carefully elides Bertha's existence in order to get his way. He tells Jane that it is her he intends to marry and that "my bride is here [...] because my equal is here, and my likeness." He even asks Jane to marry him. Technically, he is telling the truth: he does intend to marry Jane someday, and his bride is at Thornfield. But the bride who is there is Bertha, not Jane. Because Bertha is married to Mr. Rochester, she is legally bound to him and cannot walk away like Jane can. She must remain his dirty secret in the attic. Bertha, unlike Jane, has lost her mind and cannot resist the comparison to a trapped animal.
This comparison brings complexity to a central question of the novel, which is whether Bertha is responsible for destroying herself. Mr. Rochester blames her family history of mental illness and does not think he is responsible for her decline and eventual death. He believes he is only responsible for the marriage's detrimental effects on his own life. But Mr. Rochester's own simile contains ambiguity about who is to blame for the bird's destroyed feathers. He claims that the bird is responsible for "rending its own plumage." Jane, meanwhile, draws attention to the net holding the bird. Someone is responsible for trapping the bird in the net in the first place, Jane helps the reader see. The bird is only fighting for the freedom it had before a human ensnared it. The simile and underlying metaphor thus implicate Mr. Rochester in Bertha's demise in a way Mr. Rochester himself struggles to see.
In Chapter 29, Jane is safe at the Rivers family home after a brief but harrowing period of being unhoused. The chapter opens with a simile that evokes a Christian allegory of resurrection:
To that bed I seemed to have grown; I lay on it motionless as a stone; and to have torn me from it would have been almost to kill me.
Jane lies in bed for three days (or so the narrator reports). She compares herself to a stone lying on the bed, almost as though she is carved into it. This comparison conjures the idea of a sarcophagus, where the likeness of a dead person is carved into the stone tomb that contains their body. The period of three days is significant because in the Bible, Christ is resurrected on the third day after his death. Whether things happened exactly this way or not, the narrator constructs this moment in the narrative as a sort of resurrection for Jane. She went into the woods expecting to die, surrendering to God's will instead of returning to Thornfield. She follows a distant light to the Rivers cottage, as if guided by God. Her surrender to death and the afterlife sets her up to rise from the bed and get a fresh start in a home where she is neither too rich nor too poor to belong. As it turns out, the Rivers are her blood relatives—this rebirth gives Jane the chance to start her life again not as an outcast orphan, but as a welcome addition to the family.
From this moment on, there is a clear path of least resistance for Jane to follow. She could easily resolve all tensions in her family history by marrying St. John Rivers and sharing the money their uncle has bestowed on her at the Rivers' expense. She would finally belong somewhere. There seems to be a real chance, at this point, that the novel is going to veer away from the gothic and toward a more run-of-the-mill marriage plot. But Jane eventually reclaims her role as a gothic heroine by refusing to resolve her own family history in this pat way. Instead she uses her second chance at life to marry the man she loves and to resolve Mr. Rochester's troubled family history.
In Chapter 34, Diana Rivers encourages St. John to kiss Jane, just as he does his own sisters. Jane uses an imperfect simile to compare the kiss to something that might turn a person into a statue:
There are no such things as marble kisses or ice kisses, or I should say my ecclesiastical cousin’s salute belonged to one of these classes; but there may be experiment kisses, and his was an experiment kiss. When given, he viewed me to learn the result; it was not striking: I am sure I did not blush; perhaps I might have turned a little pale, for I felt as if this kiss were a seal affixed to my fetters.
The figure of speech here is difficult to pin down, which is part of its effect -- the narrator is having trouble describing the kiss. St. John's kiss is so passionless that the narrator wants to describe it as a "marble kiss" or an "ice kiss." This is a strained simile because, as she says, marble kisses and ice kisses don't exist. Throughout the novel, the narrator has hardly been reluctant to use straight metaphors, drawing comparisons that don't truly exist. For instance, she compares human nature to food. By showing her own struggle with the comparison here, she further emphasizes how off-putting the kiss is.
Jane uses another simile to describe the kiss as "a seal affixed to my fetters." Not only does she fail to blush, but she actually turns whiter, as if the almost "marble kiss" is turning her into an unfeeling marble statue. This simile is clearer: St. John may not mean to, but he is imprisoning Jane by casting her as his sister and by courting her to be his wife. Everything about Jane's situation with the Rivers family makes sense and should be desirable to her. This makes it difficult for her, on logical grounds, to refuse St. John's affection. A further complicating issue is Jane's lack of feeling for St. John. He acts as though there need not be any difference in passion between a sister and a wife. Jane, however, thinks it is important to feel passion for a spouse. This very conviction is the reason she found it difficult to stomach the idea of Mr. Rochester marrying Blanche Ingram. Jane's "fetters" (the logic of her position in the Rivers household, and St. John's encouragement of it) are icing over her emotional self, turning her less human.