 The main floor functioned as a reading room, lit by abundant natural light from the eastern windows.Shelves or "armaria" set into niches along the walls held papyrus book rolls that visitors could read, though borrowing would not have been permitted because copies of books were rare and labor-intensive to produce.Additional scrolls may have been held in free-standing book boxes placed around the room, in which case the library would have had a holding capacity of up to sixteen thousand scrolls.