How can I describe her? How can I separate her from my own sensations, and from all that has happened in the later time? How can I see her again as she looked when my eyes first rested on her—as she should look now, to the eyes that are about to see her in these pages? (220.127.116.11)
As a storyteller Walter continually has to struggle with his no-spoiler policy. He has to keep things restricted to the present moment of the story and not drop too many hints about what will happen in the future. Here, with very lyrical language, we see how hard it is for Walter to separate Laura of the past from the Laura we later learn will become his wife.
I suppose I remember them because they were kind. It's little enough I remember besides—little enough, little enough. (18.104.22.168)
Poor, crazy Anne. Doesn't her little singsong repetition at the end here make her sound nuts? Anne has a really interesting relationship to memory: she lives almost wholly in one particular moment in the past, as if frozen there. She's aware of time passing and yet she sees no reason to move on from that one life-defining moment with Mrs. Fairlie.
I at once appeal to two of the strongest feelings in her nature—to her love for her father's memory, and to her strict regard for truth. (22.214.171.124)
Nearly all the characters have some memory that clings to them and defines them. In this case, it's Laura and her father. The death of Laura's father isn't something the narrative makes a huge deal about, but her decision-making process was largely defined by it.
"You don't remember a fine spring day at Limmeridge," she said, "and your mother walking down the path that led to the school, with a little girl on each side of her? I have had nothing else to think of since, and I remember it." (126.96.36.199)
The idea that Anne has had "nothing else to think of since" is really powerful. It reveals just how damaged her mind is and how she's suffering from a case of arrested development.
[A]nd yet I saw him now, as plainly as if the past time had returned, and we were both together again at Limmeridge House. (188.8.131.52)
Sometimes the past rises up and overtakes the present for characters, particularly when they are distressed. Here Marian sees Walter in a sort of vision.
"Do you believe in dreams?" she whispered to me at the window. "My dreams, last night, were dreams I have never had before. The terror of them is hanging over me still." (184.108.40.206)
Even unreal pasts can be powerful and traumatic. Here Laura's dreams haunt her in her waking life. This scene hints at the mental trauma Laura will suffer in coming chapters, when she has a sort of breakdown.
These were the only recollections—all of them uncertain, and some of them contradictory—which could be extracted from Lady Glyde, by careful questioning, on the journey to Cumberland. (220.127.116.11)
Laura's damaged mental state, and her inability to recall the past, plays a huge role in the third part of the book, which is largely about dealing with and piecing together mysteries from the past. In a way, the third part of the book is so past-focused in order to give characters closure and let them move on to the future.
The one remaining chance […] the chance of appealing to her recollection of persons and events with which no impostor could be familiar, was proved, by the sad test of our later experience, to be hopeless. (18.104.22.168)
This sentence builds up suspense by leaving the main point (the fact that Laura's memory makes the situation "hopeless") until the very end.
We look for the body. The scorching heat on our faces drives us back; we see nothing—above, below, all through the room, we see nothing but a sheet of living fire. (22.214.171.124)
The scenes where Walter describes the fire that killed Sir Percival are among the most powerful in the novel. He switches to the present tense and seems to be really reliving the trauma.
I read these little domestic confidences, in the bright morning, with the terrible recollection of what had happened the evening before, vivid in my memory. (126.96.36.199)
Walter deals with the immediate aftermath of the fire, describing how the event haunted him the next day and for days after.
But I owed it to Marian to be faithful to my past experience of her, and to trust her as I trusted myself. (188.8.131.52)
This idea of being faithful to the past is key to Walter's character and acts as a foundation for his relationships with Laura and Marian as the novel progresses.