An Ionian who perhaps left his home city around the time the Persians conquered the area (546 BC), Xenophanes lived as a wandering minstrel, surviving into his 90s, into the earth fifth century.  Although later authors regard him as founder of the Eleatic School and the teacher of Parmenides, he seems not to have been a teacher or an Eleatic.  Rather, he practiced Ionian scientific inquiry and came to some remarkable conclusions.

He said, “For from earth are all things and into earth do all things die” (B27).  This may indicate that he had a theory of matter like those of Thales and Anaximenes, whereby one stuff turns into every other kind of stuff.  He has a basic cosmological theory: “This upper boundary of earth is visible here at our feet/ touching air; the lower reaches down without limit” (B28).  Thus it appears that the earth extends downward without end, while air extends upward without end.  From some other things he says about the sun going on without end, it appears that he believes there is an infinite plane at the surface of the earth, dividing earth from air.  (One source reports: “the earth is boundless and surrounded neither by air nor by heaven” [A32].)

Earth apparently turns into water (manifest in the seas covering the earth in many places).  And

Sea is the source of water, the source of wind;

for neither without great sea,

nor currents of rivers nor rain water from the sky,

but great sea is the begetter of clouds, winds,

and rivers.  (B30)

Thus there is a water cycle in which water evaporates, turns into winds, then condenses into cloud, then falls as rain.  Further, “She whom they call Iris [i.e. the rainbow], this too is in reality/ cloud, purple and scarlet and green to the view” (B32). 

There are cycles in which large portions of the earth are flooded and become muddy.  As evidence he cites the fact that fossils of sea shells are found in mountains and in quarries on dry land (A33).  Thus he was a kind of proto-paleontologist and geologist.  (More on him next time.)