The title of the story refers to a lamp given to Psyche by Venus by which Psyche is able to learn the identity of her lover. In Edith Wharton's story, "The Lamp of Psyche" Delia Corbett has married Laurence Corbett and is in the full flush of love at the beginning of the story. Delia and Laurence live in Paris. They take a trip to Boston to visit Delia's Aunt Mary.
The story takes place in the year 1891. We learn that Laurence is 52 years old, meaning he would have been born in 1839. Aunt Mary asks Delia what Laurence did during the war, the American Civil War, that is. Delia realizes she does not know. When Delia finally puts the question to Laurence, his answer forever alters her view of him.
This is a fascinating story for those of us who are interested in the American Civil War and its effect on women left at home. In this story, Delia had not even wondered what Laurence had done in the war, so long ago had it been, until Aunt Mary raises the question. I was struck by the thought that had Delia been from the South, rather than from Boston, her memory of the war would not have been so easily set aside.