What did you expect? The poem is about a ferry ride over the East River from Manhattan to Brooklyn – of course Whitman is going to give us the sights and sounds of the city. He paints what amounts to a panorama, which is a 360-degree view of everything within sight. Much of the imagery is breathtakingly beautiful, like the descriptions of the light from industrial foundries.
- Lines 13-16: These lines each begin with the word "Others." Beginning successive lines with the same word is called "anaphora." He imagines that other people will take the same ferry between Manhattan and Brooklyn as he does.
- Lines 17-18: Barring some sort of natural or man-made catastrophe, New York City should still be around far into the future. But even if it's not, at least the geography of its islands will be there.
- Lines 35-36: These lines contain imagery of the haze and vapor that surrounds New York at this hour. Notice the alliteration of "haze on the hills" and "vapor […] tinged with violet."
- Line 44: New York was an international shipping city, so it's not surprising that the ships in port fly "flags of all nations."
- Lines 60-61: The speaker discusses his personal connection to the city. He lived in Brooklyn and liked to walk around Manhattan, and to swim in the waters around the island. Don't try this at home: those waters are filthy now.
- Line 81: The speaker coins a word for people who are native to Manhattan: "Manhattanese."
- Line 114: The speaker alludes to the Native American heritage of New York by using the word "Mannahatta." Politically correct? Maybe not. But it's the 19th century, people.