  The rotation begun by nous ultimately affects phenomena on the earth and above the surface of the earth. Anaxagoras claims that the earth is flat, rests on air, and remains where it is because of its size (A42; a number of geological and meteorological views attributed to Anaxagoras were also apparently held by Anaximenes; whether this is because Anaxagoras was following Anaximenes or because the commentators conflate the two is unclear). Despite the manner of its formation, the earth is stationary, not spinning. The (relative) flatness of the earth allows water to spread over the earth, with mountains and plains rising above the level of the water. The levels change as water is evaporated or added by rain, and as water that has been trapped in the earth by the rotation makes its way out through rivers to the sea. Because the air under the earth is also moving (pushed along by the cosmic rotation), it sometimes gets caught up in the crevices of the earthy stuff. When this air cannot make its way out, the force of the moving air causes earthquakes. Anaxagoras seems determined to explain everything. The extant sources report views on thunder and lightning, the source of the Nile, the first correct account of the nature of hail, and inquiry into why the sea is salty. He also offered accounts of sense perception and made inquiries into embryology.