What does Scout realize at the beginning of chapter 16 that Jem already understands?

In is
confronted at the jailhouse by an angry group of men. He is at the jailhouse to make sure that
no harm comes to Tom Robinson, a defendant of his who has been falsely accused of raping and
beating a white girl. The men insist that Atticus lets them through, but Atticus
refuses.

At the point when the tension between Atticus and the men seems to
threaten violence, , unaware of how dangerous the situation is, makes her presence known. , who
is also present, fully understands how dangerous the situation is. When Atticus tells him (along
with Scout and Dill) to leave, Jem refuses. Jem knows that the group of men pose a real threat
to his father, and he knows that it is likely only the presence of the children that is
preventing the men from hurting his father. Scout, on the other hand, is oblivious to the danger
that Atticus is in.

At the beginning of , when they are all back at home,
Scout remembers her father, at the jailhouse, "calmly folding his newspaper and pushing
back his hat." This reminds her of another moment, from , when, confronted by a rabid dog,
Atticus "push(ed) up his glasses." At this moment Scout realizes what Jem has known
all along, namely that the angry men at the jailhouse posed just as much of a threat to her
father as did the rabid dog. This realization is what Scout is referring to when she says,
"The full meaning of the night's events hit me."