Calpurnia passes Atticus a note saying that his children have gone missing. It's then revealed that they've been sitting up in the balcony all along. Atticus tells them to go home and eat dinner, and if the jury hasn't come back by the time they return, then they can stay and watch the verdict. The children are gone for about an hour, in which time Calpurnia scolds them, Aunt Alexandra nearly faints, and Jem proudly claims that Tom should be acquitted. Atticus knows that he won't be, but refrains from telling Jem this. When they get back, the courtroom is just as they've left it, and the Reverend has even saved their seats.
Scout nearly falls asleep before the verdict comes back: guilty. She watches as in a dream as her father walks down the aisle toward the door. All of the African Americans stand up as he passes out of respect, and Scout stands with them.
Calpurnia uses an idiom when she tells the children she'll "skin every one of [them] alive."
Swimming. Once again, Lee uses the image of an underwater swimmer to indicate when events happen very slowly (or at least appear to). This time, it's the jury who appear to move slowly as they return to announce the verdict, whereas Atticus, who has been described as an underwater swimmer once before, moves surprisingly quickly after Tom is convicted. The speed with which he leaves might indicate that he's upset about the verdict.
An example of this is the the courthouse clock "suffer[ing]" the strain of keeping time.
One example of this would be when Scout refers to Jem as Calpurnia's "precious Jem," punning on the phrase "precious gem," which is meant to indicate how highly Calpurnia thinks of Jem.
Scout uses a simile when she says that the feeling in the courtroom was the same as that of a cold February morning when everything went still, even the mockingbirds. This stillness is a result of both anticipation and fear, as Tom and the spectators await the verdict.
Calpurnia's Apron. When Calpurnia arrives in the courthouse, she's wearing "a fresh apron." This is notable for two reasons: that the apron is fresh, meaning that she must've changed it to go out in public, and that she wears it even inside the courthouse, though she's only required to wear it inside of the Finch house. Her apron is thus a symbol both of her servitude and of her pride, because she makes sure to always look clean, fresh, and proper. She might be a servant, but she's a respectable (and very formidable) woman, and that is clear from the way she wears her apron.
Time. Lee continues to build on the theme of time by slowing it down while everyone waits to hear the verdict. She draws on the motif of swimming and swimmers to indicate that time is moving very slowly and that Scout's perception of time is affected by her physical and emotional state (she is worn out after the long trial). It's telling that nearly every scene where time has slowed down for Scout corresponds to an event that she has trouble understanding: the trial, her father's skill as a marksman, and Mrs. Dubose's fight against addiction.