Get out the microscope, because we’re going through this poem line-by-line.
Lines 1-2
How many dawns, chill from his rippling rest
The seagull's wings shall dip and pivot him,
- The poem opens on the image of a seagull taking off in flight.
- The image places us on a body of water – specifically the East River. The Brooklyn Bridge spans this river, connecting Manhattan and Brooklyn.
- The time is dawn, symbolic of beginnings. But this is not one particular dawn, it's the "many dawns" in which the scene can be witnessed.
- "How many dawns" has a timeless quality, the endless repetition of taking flight in the morning.
- The seagull is cold, "chill," from his "rippling rest." That is, the gull has been sitting on the rippling waters.
- The "dip" and "pivot" of the gull's flight provide vivid descriptions of motion. These words also reply to the visual appearance of a suspension bridge, with the "dips" of its cables, "pivoting" from high to low.
Lines 3-4
Shedding white rings of tumult, building high
Over the chained bay waters Liberty--
- The seagull flies in circles above the bridge, higher and higher.
- In the poet's mind, the wings of the gull create "tumult" in the air as they pass. The word "tumult" also means "chaos" or "disorder," to which the order and form of the bridge provide a stark contrast.
- The gull is colored white," and whiteness also suggests white-capped waves in the water and the color of the dawn air.
- The bird is like an architect – it "builds" a pattern over the bridge. In a sense, it even builds the bridge itself, an act of rebirth each morning.
- The waters of the bay appear to be "chained' because they lie in the shadow of the chains of the Brooklyn Bridge.
- The last word of the stanza is mysterious – "Liberty."
- Literally, the bird passes the Statue of Liberty. But "Liberty" is also what the bird has been "building." Flight is a common symbol for freedom.
- By extension, the Brooklyn Bridge is a symbol of liberty, freedom of movement, freedom of ideas, etc.