I would say it's the Historian because they study history or the past and have to interpret it so they can figure out how to teach it or stop it from happening again.
Answer:
swinging from birches as a boy
Explanation:
The people will have journeyed to the center of the earth. I think this because it is the title. This is fantasy because the center of the earth is too hot to travel to. The people will probably get burnt next.
The mood of that line definitely is frustrated.
Hope this helps. :)