A metaphor to s simply used to compare things that are quite different even though there's something common to them. This is the figurative language that is used in the excerpt above.
First, harshness was compared to Black Southern life because they've a common symbolism even though they are different. This can be seen in the excerpt where it was written that "The Black Southern Life was denoted as being harsh".
Also, another comparison in the excerpt "The early morning was softened by nature's blessing of grogginess, forgetfulness, and the soft lamplight"
