Page:Early Greek philosophy by John Burnet, 3rd edition, 1920.djvu/82

68 There is a curious variation in the figures given for the size of the wheels of the heavenly bodies, and it seems most likely that 18 and 27 refer to their inner, while 19 and 28 refer to their outer circumference. We may, perhaps, infer that the wheels of the "stars" were nine times the size of the earth; for the numbers 9, 18, 27 play a considerable part in primitive cosmogonies. We do not see the wheels of fire as complete circles; for the vapour or mist which formed them encloses the fire, and forms an outer ring except at one point of their circumference, through which the fire escapes, and that is the heavenly body we actually see. It is possible that the theory of "wheels" was suggested by the Milky Way. If we ask how it is that the wheels of air can make the fire invisible to us without becoming visible themselves, the answer is that such is the property of what the Greeks at this date called "air." For instance, when a Homeric hero is made invisible by being clothed in "air," we can see right through both the "air" and the hero. It should be added that lightning is explained in much the same way as the heavenly bodies. It, too, was fire breaking through condensed air, in this case storm clouds. It seems probable that this was really the origin of the theory, and that Anaximander explained the heavenly bodies on the analogy of lightning, not vice versa. It must be remembered that meteorology and astronomy were still undifferentiated, and that the theory of "wheels"