Although I've seen yellow semen it wasn't healthy.  When you think about our atavistic responses does yellow ever come up as a healthy colour - for people anyway, lets leave flowers out of this. The yellow fog is pervasive and if not frankly purulent in it's invasiveness ( broken in its march by the feline curling to sleep on that soft October night) it is a relief when white arms, albeit with light brown hair, show up. And a less reassuring relief when the mens' arms are sleeved and their smoke contained by pipes. And still implied at the end with peach juice threatening those white flannel trousers, before the unreachable white hair of the waves.
 
I find the proposal of priapic chimneys unconvincing not because soot is so remote from semen in hue and texture to be tiresomely furtive as a device but because I wouldn't presume to suggest Eliot would use a chimney as phallic symbol. Corney or something you know.
 
 
Cheers Pete.
Whatever that sinewy yellow fog/semen is, it's no bull.

Cheers,
Peter.

Dr. Peter C. Montgomery