Space and Environment- At The Earth's Core

Yesterday we were given the beginnings of our first assignment, to do a series of sketches based on excerpts from a classic book. I was given "At The Earth's Core",  which after some research I discovered was a fantasy novel written in 1914 by Edgar Rice Burroughs about a world inside of a hollow earth. My first thought was that any book written by someone called Edgar was going to be pretty good (What happend to names like that?). I went through the excerpts and highlighted all the bits I think might help me later- anything describing the setting/ environment.