At what sight do the narrator and the old man gaze during their discussion of the Memory Police in Chapter 7?

As the narrator and the old man talk about the Memory Police and the latest disappearances, they are sitting together on the old man's boat. As they talk, they watch the river empty the last of its remaining rose petals out into the sea. By the end of the discussion in Chapter 7, it is dusk, and the narrator states, "No matter how long I peered into the distance, I could no longer make out the petals" (54).