Boys have an avantage to go to school if you were greece you would be counted for not a person boys and girls cant go to the same school they have to be seprated and girls have to stay at home and learn to clean and cook. Boys have to learn how to farm and hunt.
This changes when Atticus shoots the mad dog. They find out that he is a sharp shooter and was infamous in the county as one-shot Finch. They were now proud of their father. Jem is confused that his father has kept this a secret and at first wants to know why Atticus would not be proud and brag about this ability.
The reason Jem won't allow Scout to brag about Atticus's talent is because he wants to be a gentleman like his father and understands that having the ability to shoot beings is not something to take pride in.
Tantalus, Tityos, and Sisyphus are in Tartarus. It was a place for punishing those who have sinned gravely, and those three certainly were sinners in the eyes of Greek Gods.
It helps define the theme by providing the contrast of a river as opposed to a town. A river is forever flowing,free, and untamed, it represents freedom. While a town has structure, and rules, and ways in which is must 'act'. This represents slavery.