What is the emotional tone of the line "The curfew tolls the knell of parting day"?

The line "The curfew tolls the knell of parting day" conveys a melancholic tone primarily through its imagery and associations. The word "curfew" suggests the conclusion of activities and the onset of nighttime, symbolizing an end or a closing chapter. The phrase "tolls the knell" evokes the sound of a death bell, which traditionally marks mourning or loss, further reinforcing a sense of sadness. Additionally, "parting day" implies farewell and the inevitable passage of time, contributing to an overall feeling of melancholy. This line reflects not just a physical transition from day to night, but also an emotional transition filled with a sense of longing and reflection on loss, making the melancholic interpretation the most fitting.