What is the literary term for a very regular rhythm in a poem

taken from the novel “the adventures of huckleberry finn” by mark twain (1884), the author narrates about social issues and norms related to morality, prejudice, and slavery. twain included the excerpt above in order to discuss a moral conflict that huck is in: following the moral values he has received from the society in which he lives. moreover, there are moral issues such as gilt and blame discussed here. in the excerpt above, which is part of chapter xvi, huck faces a dilemma: jim to escape or telling miss watson about jim’s flight. huck feels confused, since by choosing one action or another someone is going to get hurt. both jim and miss watson have him in different ways; jim has protected him and has been very kind with him and miss watson has him with his education. the following sentence is a clear example of the dilemma huck faces when he narrates what his conscience tells him: “what had poor miss watson done to you that you could see her niger go off right under your eyes and never say one single word? ”.