Book,  chapter

1    1,   13| insufficient safety valves for the subterranean vapors, that shocks are
2    3,   10|         immense cauldron hung over subterranean fires. The ground vibrates
3    3,   13|           of vapor, the product of subterranean fires.~This phenomenon of
4    3,   14|          vapors ready to hand, and subterranean fires ready to issue forth.
5    3,   14|        prevented the egress of the subterranean fire. If they could move
6    3,   15|           twenty miles square, the subterranean forces had a field for the
7    3,   20|          through the action of the subterranean fires, but for ages back