I think the picture that Eliot portrays in this writing is one of old age and what it means for your life to make a difference and matter. A portion of the writing that best illustrates this is around line 115 when he is writing that he wasn't meant to be a prince but was instead intended to be an advisor to the prince who sometimes, makes a fool of himself. I see Eliot as being vulnerable in this poem especially when describing all the effects of growing older (lines 40-45). It is obvious that he feels like his better days are over and that his eternal future is close at hand (lines 84-85). I think something that frightens Eliot is being misunderstood by society around him. I interpreted this from the writing, "That is not it at all, that is not what i meant, at all." (lines 97-98). I think he wants to be properly understood as a person and he also wants his work and life to be worth something which can only happen if he is properly understood.
Eliot's writing reminds me again of Whitman a little when he writes about the "yellow smoke" and "fog." Both writers seem to personify various aspects of nature in order to make a point and when Eliot does it here, I think he is trying to illustrate the brevity and complexity of a life. Similar to "yellow smoke," we are rushing around looking for the opportune moment wondering if there is enough time and contemplating certain actions we may or may have not made and before you know it we are gone and we disappear.
One question I have- Who are the mermaids at the end of the poem? What do they represent?