A particular feature of the valley of ashes is the billboard on which are portrayed two disembodied "blue and gigantic" eyes, with "retinas one yard high". The eyes look out through "a pair of enormous yellow spectacles". The oculist, Doctor T.J. Eckleburg, whose business they advertise, has probably now himself sunk down "into eternal blindness", or else moved away and forgotten about the advert.
Tom has bought a small apartment in 158th Street in New York where he can meet his mistress, Myrtle. The first description of the building as "a long white cake of apartment-houses" echoes Daisy's room with its "wedding cake frosted" ceiling. However, although Myrtle feels very proud of her apartment (she casts a "regal" glance at it) it is clear Tom has not spent much money on it:
The important confrontation between Gatsby and Tom takes place here. The room is described as "large and stifling", the heat is a metaphor for the emotional tension that is building.
Nick had already described the weather as "broiling", noting in the train on his way to Daisy's that the "straw seats of the car hovered on the edge of combustion."
Nick notes how the "compressed heat exploded into sound" as they hear the Mendelssohn's Wedding March from the ballroom below. This seems like a mocking comment on Tom and Daisy's relationship as both are engaged in adulterous affairs.