1846: James Dwight Dana: "On the volcanoes of the Moon" American Journal of Science 2, New Haven, CT.
Dana, one of the first geologists to visit the Hawaiian Islands, believed
that lunar craters were not volcanoes like Vesuvius and Etna, but
more like the broad cratered Hawaaian caldera Kilauea. Like lunar
craters, Kilauea "is a vast open pit,...has clear bluff walls... [and] The
bottom is a plain of solid lavas, entirely open to the day..." Dana also
realized that lunar lavas, because of the 1/6th gravity, "would become
more blown up with the vapors, or more spongy." compared to
terrestrial lavas. He used this correct inference, to wrongly state,
"unhesitatingly, without fearing an impeachment of our sobriety," that
the lunar crater rims were formed of overflowings of lava.
Like many other 19th century scientists, Dana believed that the Moon
(and Earth) formed in a molten state and its progressive cooling
resulted in the formation of smaller and smaller craters. His happy face
drawing of the lunar crater Heinsius indicated such "successive
diminuations"
