The next stage is the separation of the air into clouds, water, earth, and stones (fr. 16). In this Anaxagoras follows Anaximenes closely. In his account of the origin of the heavenly bodies, however, he showed himself more original. We read at the end of fr. 16 that stones “rush outwards more than water,” and we learn from the doxographers that the heavenly bodies were explained as stones torn from the earth by the rapidity of its revolution and made red-hot by the speed of their own motion.[710] Perhaps the fall of the meteoric stone at Aigospotamoi had something to do with the origin of this theory. It may also be observed that, while in the earlier stages of the world-formation we are guided chiefly by the analogy of water rotating with light and heavy bodies floating in it, we are here reminded rather of a sling. Footnote 710: Aet. ii. 13, 3 (_Dox._ p. 341; R. P. 157 c). [Sidenote: Innumerable worlds.] 134. That Anaxagoras adopted the ordinary Ionian theory of innumerable worlds is perfectly clear from fr. 4, which we have no right to regard as other than continuous.[711] The words “that it was not only with us that things were separated off, but elsewhere too” can only mean that Nous has caused a rotatory movement in more parts of the boundless mixture than one. Aetios certainly includes Anaxagoras among those who held there was only one world; but this testimony cannot be considered of the same weight as that of the fragments.[712] Zeller’s reference of the words “elsewhere, as with us” to the moon is very improbable. Is it likely that any one would say that the inhabitants of the moon “have a sun and moon as with us”?[713] Footnote 711: See above, p. 300, _n._ 684. Footnote 712: Aet. ii. 1, 3. See above, Chap. I. p. 63. Footnote 713: Further, it can be proved that this passage (fr. 4) occurred quite near the beginning of the work. Cf. Simpl. _Phys._ p. 34, 28, μετ’ ὀλίγα τῆς ἀρχῆς τοῦ πρώτου Περὶ φυσέως, p. 156, 1, καὶ μετ’ ὀλίγα (after fr. 2), which itself occurred, μετ’ ὀλίγον (after fr. 1), which was the beginning of the book. A reference to other “worlds” would be quite in place here, but not a reference to the moon. 135. The cosmology of Anaxagoras is clearly based upon that of Anaximenes, as will be obvious from a comparison of the following passage of Hippolytos[714] with the quotations given in Chap. I. (§ 29):— (3) The earth is flat in shape, and remains suspended because of its size and because there is no vacuum.[715] For this reason the air is very strong, and supports the earth which is borne up by it. (4) Of the moisture on the surface of the earth, the sea arose from the waters in the earth (for when these were evaporated the remainder turned salt),[716] and from the rivers which flow into it.