I think the sea might symbolize a place that brings comfort, yet also brings sadness. I the first couple of sentences, the text shows how the sea is calm and how the air smelled sweet, revealing that the sea was a place that brings you comfort. Another part that supports the sea being a place that brings comfort and sadness in the last sentence which reads "...Begin, and cease, and then again begin, with tremulous cadence slow, and bring the eternal note of sadness in." This reveals that although the sea brings comfort and tranquility, it too does bring sadness.
