Undine has been in Paris for a year when Indiana Frusk comes to visit her in Chapter 24. The narrator depicts the environment around this scene, then compares it to Undine's feelings through a simile:
Not much more than a year had elapsed since Undine Marvell, sitting in the drawing-room of another Parisian hotel, had heard the immense orchestral murmur of Paris rise through the open windows like the ascending movement of her own hopes. The immense murmur still sounded on, deafening and implacable as some elemental force; and the discord in her fate no more disturbed it than the motor wheels rolling by under the windows were disturbed by the particles of dust that they ground to finer powder as they passed.
The narrator recalls a time a year before when Undine felt that the city sounds around her were "like the ascending movement of her own hopes." Undine's hopes swell with the "orchestra" of city sounds outside, as the entire environment combines to tell her story.
But a year later, talking to Indiana, the relation of Undine's emotions to the sounds of the city collapses. This time, those same sounds are continuing "deafening and implacable as some elemental force": the environment is no longer changing to match Undine's emotions. The "discord in her fate"—her recent divorce from Ralph, her abandonment by Peter—has no effect on the sounds around her. This simile, comparing Undine to her environment, helps to show the changes in her character over time; after multiple failed partnerships, Undine has an inkling that the world will not always bend to her whims.