Stephen's extensive recollections in Proteus of the time that he spent in Paris, after his university days and prior to his mother's death, are anticipated by one such memory in Nestor. The "library of Saint Genevieve," located on the Place du Panthéon, contains a large reading room that is magnificent but utterly lacking in overhead illumination. It would have been quite dramatically dark as Stephen read there "night by night," and he takes the darkness as a metaphor for his own mind. On the desks were "glowlamps" that cast circles of light for reading.
Gifford notes that, according to the 1907 edition of Baedeker's Paris and Its Environs, the library was full of students in the evening hours. During those dark hours, he suggests, the arching iron frame beneath the room's roof creates the effect of being in a cave, bringing to mind passages from Blake's The Marriage of Heaven and Hell: "I was in a Printing house in Hell, & saw the method in which knowledge is transmitted from generation to generation. . . . In the first chamber was a Dragon-Man, clearing away the rubbish from a cave's mouth; within, a number of Dragons were hollowing the cave." Blake's demonic dragon-men are associated, in Stephen's thought as in the poem, with writers, bookmakers, and libraries. He places his own mind in "a sloth of the underworld, reluctant, shy of brightness, shifting her dragon scaly folds."