What is the central idea of the text so far

Stone, two or three feet thick, the door of wood and iron, a foot thick, and the iron grating which strained the light, i could not being struck with the foolishness of that institution which treated me as if i were mere flesh and blood and bones, to be locked up. i wondered that it should have concluded at length that this was the best use it could put me to, and had never thought to avail itself of my services in some way. i saw that, if there was a wall of stone between me and my townsmen, there was a still more difficult one to climb or break through before they could get to be as free as i was. i did not for a moment feel confined, and the walls seemed a great waste of stone and mortar. i felt as if i alone of all my townsmen had paid my tax. — “civil disobedience,” henry david thoreau based on this passage, how did thoreau feel about his confinement?

Does anyone know the answers to these two? i don’t want to have to guess, you!

What do the words “briefer,” “too beautiful to stay,” and “sleep of death” in the last stanza of wylie’s prom suggest about nature’s bounty and a life of plenty and ease?