Above we see a sectional view of the Earth, revealing its "central fire" and active volcanoes from 1665's "Mundus Subterraneous" by Athanasius Kircher. The Jesuit polymath researched and wrote on a variety of scholarly topics, but this beautifully-illustrated tome served as the culmination of his geological interests.
It's worth noting that Kircher provided a mostly-correct explanation of how igneous rock forms, and provides a view of the inner Earth that's appropriately complex and grounded in natural processes. But he draws in various erroneous theories as well, everything from the lost continent of Atlantis to giants and dragons that reside in the subworlds. As always, you have to judge such a text within the context of its own time.
I can't do the work justice here, but the Public Domain Review features an excellent overview of the book and its author right here.
Now let's look at an additional illustration that shows us how the planet's "fire and water sweetly conspire together in mutual service."