From the very first line, the speaker associates the "femme" with the Sargasso Sea, and this turns out to be the beginning of an extended metaphor, as the woman's personality and interactions are consistently represented by sea imagery throughout the poem. The speaker never indicates that the woman herself has any real connection to or interest in the Sargasso Sea (in fact, she seems to be a longtime resident of London). He might have come across this association because the Sargasso Sea is famous for collecting masses of seaweed and debris, thanks to the ocean currents surrounding it. The speaker seems to see the woman as having a similar, whirlpool-like nature in the way she collects "Ideas, old gossip," and "Strange spars of knowledge" (4-5). For more about this, check out what we say in "Setting."
- Line 1: The speaker establishes straight off the bat that the Sargasso Sea is a metaphor for the woman – technically, for both the woman's mind and herself, whatever that means. It's weird that the speaker insists on separating the woman from her mind but then gathers them back together into a metaphor that is a single entity, the sea.
- Line 3: We're guessing that the "bright ships" described here symbolize the various visitors the woman has, the "Great minds" that seek her out (6) and leave her with ideas, gossip, and knowledge (4-5).
- Lines 2, 12, 16, 27: In these lines the speaker uses words that describe movement we see primarily on water, such as objects sweeping about, floating or being fished up.
- Line 23: The inclusion of ambergris here is interesting, because it's a secretion produced by whale intestines, which adds to the general sea imagery. But it's also known as an important ingredient in perfume, which immediately recalls a bourgeois lady waiting on various guests in her salon. Ambergris can symbolize both the wilderness of the sea and the civilization of land.
- Line 25: The word "sea" in "sea-hoard of deciduous things" has two functions. It can be read literally, to indicate that a "hoard" (a hidden or stored supply) of things are actually in the sea. Or it can be read figuratively to refer to a really large group of things (a horde that is "as big as the sea").
- Line 26: Like "sea" above, the word "sodden" has a double meaning. It indicates that the "strange woods" are damp or soggy – which they certainly would be if they were floating in water. "Sodden" can also mean dull, worn-down, and sluggish (such as when we say, "That old alcoholic has really sodden features"), which could make the "strange woods" a metaphor for objects or people floating through the woman's life in London, rather than through the sea.