Franklin to Abbé Geologist Jean-Louis Giraud Soulavie

(...)"parts of the globe might be air compressed. And as the force of expansion in dense air when heated, is in proportion to its density, this central air might afford another agent to move the surface, as well as be of use in keeping alive the central fires; though, as you observe, the sudden rarefaction of water, coming into contact, without those fires, may be an agent sufficiently strong for that purpose, when acting between the incumbent earth and the fluid on which it rests.
If one might indulge imagination in supposing how such a globe was formed, I should conceive, that all the elements in separate particles being originally mixed in confusion, and occupying a great space, they would {as soon as the Almighty first ordained gravity, or the mutual attraction of certain parts, and tbs mutual repulsion of others, to exist) all move towards their common centre: That the air being a(...)".