It will be observed that we only hear of three circles, and that the circle of the sun is the highest. The circle of the stars presents some difficulty. It is, in all probability, the Milky Way, the appearance of which may well have suggested the whole theory.[134] It seems that Anaximander must have thought it had more “breathing-holes” than one, though the tradition is silent on this point. There is not the slightest reason for supposing that he regarded it as a sphere. He could not have failed to see that a sphere so placed would make the sun and moon permanently invisible. What, then, are we to say of the fixed stars that do not lie in the Milky Way? There seems to be no way of accounting for them unless we assume that they are the “innumerable worlds” which we have just discussed. As the fire and air which surrounded the world have been broken up into rings, we must be able to see right out into the Boundless, and the fixed stars must be just the worlds, each surrounded by its fiery envelope. It does not seem possible to explain all we are told in any other way; and, if this is right, the statement of some authors, that Anaximander regarded the stars of heaven as gods, may be more than the mere mistake which it is now generally taken to be.[135] Footnote 134: It cannot be the Zodiac; for the planets were not separately studied yet. Footnote 135: The _Placita_ and Eusebios both have τοὺς ἀστέρας οὐρανίους instead of τοὺς ἀπείρους οὐρανούς (see above, p. 65, n. 2), and it seems just possible that this is not a mere corruption of the text. The common source may have had both statements. I do not, however, rest the interpretation given above on this very insecure basis. Quite apart from it, it seems to be the only way out of the difficulty. The explanation given of thunder and lightning was very similar. They too were caused by fire breaking through compressed air, that is to say, through the storm-clouds. It seems probable that this is really the origin of the theory, and that Anaximander explained the heavenly bodies on the analogy of lightning, not _vice versa_. That would be in perfect agreement with the meteorological interest of the time. [Sidenote: Earth and sea.] 20. We turn now to what we are told of the origin of earth and sea from the moist, cold matter which was “separated off” in the beginning, and which filled the inside of the sphere of flame:— The sea is what is left of the original moisture. The fire has dried up most of it and turned the rest salt by scorching it.—Aet. iii. 16, 1 (R. P. 20 a). He says that the earth is cylindrical in form, and that its depth is as a third part of its. breadth.—Ps.-Plut. _Strom._ fr. 2 (R. P. _ib._).