Pond as simile for eyes
Charlotte, when experiencing a strong emotion, has green flecks in her brown eyes "like leaves in a trout pool". Her daughter Clementina has paler eyes but similar green flecks.
Muted keyboards as simile for sensitive people
Sensitive souls were "like muted keyboards" in that fate manipulated them soundlessly and without drama.
Gridiron as simile for New York
New York is described as having been laid out "like a gridiron" with parallel streets and perpendicular avenues. This suggests a utilitarian, unimaginative design.
Drowning as simile for sorrow
Delia sees Charlotte's face drooping like that of "a drowning face under water", meaning that it is blurry. The water in question comes from Delia's own tears.
Sword of Damocles as simile for Delia's needle
Delia's sharp embroidery needle is compared to the sword of Damocles, which famously hung by a hair. Delia is about to take a big risk by trying to sabotage Charlotte's marriage without revealing Charlotte's secret. One wrong word, and Charlotte's reputation and life will be ruined, or Clementina will be sent to a foundling home, or Joe Ralston will decide to move forward with the marriage.
