I Capture the Castle guests describe each other in terms of famous artists. Topaz is called a work by William Blake, Rose is said to resemble Emma, Lady Hamilton, the muse of the painter George Romney, Simon says that Cassandra is like "Girl with a Mousetrap," a painting by Joshua Reynolds, and Mrs Fox-Cotton is said to be a work by Salvador Dalí "with snakes coming out of her ears". Simon introduces Cassandra to the works of Claude Debussy: "Clair de lune", "La cathédrale engloutie", "La terrasse des audiences du clair de lune". She also listens to J. S. Bach's "Sheep May Safely Graze"
Au clair de la lune she is singing him into drowsiness. I am on the floor, as usual among the chair legs, and I crawl behind my mother's chair because I do not like the song she is singing and do not want her to see what it does to me. She sings: "Au clair de la lune; Mon ami, Pierrot; Prête-moi ta plume; Pour écrire un mot." Then the vowels darken ominously. My mother's voice deepens dramatically, as if she were singing in a theater. This was the part of the song I disliked most, not only because I knew that it was sad,