What are two ways in which Atticus is heroic in the novel To Kill a Mockingbird?

There are several scenes in which Atticus bravely defends others in the face of danger. In Chapter 10, a rabid dog staggers down the main road of Maycomb. Sheriff Tate gives his gun to Atticus because he knows Atticus is an expert marksman. Atticus reluctantly takes the weapon and kills the dog in one shot. By killing the rabid dog, Atticus saves the citizens of Maycomb from a dangerous threat. His actions would be considered heroic.

Another scene in the novel where Atticus would be described as being heroic takes place in Chapter 15. Before the trial, Atticus decides to sit outside of Tom Robinson's jail cell to make sure nothing happens to him. Sure enough, the Old Sarum bunch arrives and attempts to lynch Tom. Although Atticus is outnumbered and surrounded, he refuses to leave. Fortunately, Walter is able to see the error in his judgment when Scout arrives, and the mob decides to leave. Atticus's bravery in the face of danger would be considered heroic. Atticus essentially saves Tom Robinson's life by refusing to leave the jailhouse.