You are a person of some interest, one comes to youAnd takes strange gain away: (14-15)
Again we have the "you are..." format, and again we're left unsure of what the speaker really means. Check out the vagueness is here, with phrases like "some interest" and "strange gain." What kind of interest? How much interest? What about this "gain" makes it strange?
No! there is nothing! In the whole and all,Nothing that's quite your own. Yet this is you. (28-30)
The speaker is a master at making us think he is telling us something very clearly but leaving us totally confused. So here is a 30-line poem, filled with references to London, the Sargasso Sea, ships, furniture, and oceanic debris, which the speaker claims will produce a picture of a woman. We read through all these lines and try to piece them together to figure out who this woman is, only for the speaker to announce at the very end that, actually, nothing really belongs to her, and that this nothingness is her. What? You might notice that the last line is indented. Could this mean that the "this" (of "this is you") refers back to the entire poem (everything said in the last 29 lines), rather than just the "nothing" of the previous line?