Extended Metaphor
Ruth Yeazell has written an analysis of how a metaphor in the language of the narrator of James' fiction ends up actually affecting particular plot points. Typically, we differentiate between the discourse of a narrator, who talks about characters through his own words, and the discourse of characters, who could potentially be directly quoted in their thoughts. However, James employs a technique whereby he takes a metaphor that seems to be the language of the narrator, and then allows the character to look as if he is thinking through this metaphor. Once the character employs this metaphor in his thought, the logic of the language of the metaphor affects what he does, rather than what the metaphor represents itself. So for example, on page 307, Osmond compares a lady's mind to a reflective surface. We might first think of a mirror as a reflective surface. However, the narrator goes on to describe how Osmond's understanding of a surface is like that of a "silver plate." This then ends up making for a place upon which one can put "ripe fruits," one can give a "decorative value" to such a surface. This allows for us to understand how Osmond is not just interested in his pure reflection, but also for the use Isabel will have to serve as a false representative for his own self.
Ships
Ralph compares Isabel to a ship when he says he would like to "put a little wind in her sails" by giving her some money. Voyages by ship are associated with freedom and novelty, so the comparison indicates that Ralph would simply like to help her become freer.
Music
When Ralph and Isabel argue about her decision to marry Osmond, Ralph's response strikes Isabel as a "false note." Music is often used as a metaphor for James in social interactions -- when something is off about a social interaction, one person is found to have struck the wrong key or note, as if in a musical score. Notably Isabel meets Madame Merle when Merle is playing piano beautifully. This indicates that Merle hardly ever strikes a false note: she is very good at making social relationships appear harmonious.
Glass/Reflections
When glasses are presented, it is a simile for the particular point of view that a certain situation offers, and the uniqueness of a person's vision. So, for example, when Isabel discovers that Madame Merle is treacherous, and she bumps into her at Pansy's convent, she sees it "as if" she sees through a large clear glass. It is also used in James' preface to show how each person has their own particular pair of glasses that offer a unique vision to them. This means they can attribute their own meanings to certain situations and events because they are original individuals.
A kiss like white lightning
When Caspar kisses Isabel at the end of the novel, she perceives this kiss to be like white lightning. This simile refers to the shock and violence of sexual arousal for Isabel, at the same time the simile disguises the nature of Isabel's sexuality. Similes offer more vivid description in some sense, at the same time this very vivacity can be used to disguise and aestheticize the vulgarity of the truth.
