Both events in Chapters 21-22 demonstrate the way that humans can be deceived and challenged, and how easily a strong character can either change the intentions of humans or trick them completely. Juxtaposing the two events, or placing them next to each other, demonstrates this through focusing the reader on the similarities between the events. After all, Colonel Sherburn successfully challenges the mob that, apparently in moral outrage, are going to lynch him. He shows how his strength of character is enough to change the intentions of a group of men far more numerous than himself. At the circus, it is one man again who is able to demonstrate that he can trick everybody, not just the audience, but the ringmaster too, by pretending to ride while drunk. Note how the ringmaster responded:
Then the ringmaster seen how he had been fooled, and he was the sickest ringmaster you ever see, I reckon. Why, it was one of his own men! He had got up that joke all out of his own head, and never let on to nobody.
Both events therefore reveal the capacity of men to be taken in, deceived and also influenced by others. The message is clear: Twain obviously thinks that humans are a fickle species, and very easily led and deceived. This is a theme that is reinforced throughout the novel.