IV. This pleased Apollonides. ‘What a fresh way of putting a view; that was a bold man, and there was poetry in him. But how did the refutation proceed on your side?’ ‘In this way’, I answered. ‘First, the outer ocean is uniform, a sea with one continuous stream, whereas the appearance of the dark places in the moon is not uniform; there are isthmuses, so to call them, where the brightness parts and [Sidenote: C] defines the shadow; each region is marked off and has its proper boundary, and so the places where light and shade meet assume the appearance of height and depth, and represent very naturally human eyes and lips. Either, therefore, we must assume that there are more oceans than one, parted by real isthmuses and mainlands, which is absurd and untrue; or, if there is only one, it is impossible to believe that its image could appear thus broken up. Now comes a question which it is safer to ask in your presence than it is to state an answer. Given that the habitable world is “equal in breadth and length”,[306] is it possible that the view of the sea as a whole, thus reflected from the moon, [Sidenote: D] should reach those sailing upon the great sea itself, yes, or living on it as the Britons do, and this even if the earth does, as you said that it does, occupy a point central to the sphere in which the moon moves?[307] This’, I continued, ‘is a matter for you to consider, but the reflexion of vision from the moon is a further question which it is not for you to decide, nor yet for Hipparchus. I know, my dear friend [that Hipparchus is a very great astronomer], but many people do not accept his view on the physical nature of vision, since it is probably a sympathetic [Sidenote: E] blending and commixture, rather than a succession of strokes and recoils such as Epicurus devised for his atoms. Nor will you find Clearchus ready to assume with you that the moon is a weighty and solid body. Yet “an ethereal and luminous star”, to use your words, ought to break and divert the vision, so there is no question of reflexion. Lastly, if any one requires us to do so, we will put the question, how is it that only one face is seen, the sea mirrored on the moon, and none in any of all [Sidenote: F] the other stars? Yet reason demands that our vision should be thus affected in the case of all or of none. But now,’ I said, turning to Lucius, ‘remind us which of our points was mentioned first.’ V. ‘No;’ said Lucius, ‘to avoid the appearance of merely insulting Pharnaces, if we pass over the Stoic view without a word of greeting, do give some answer to Clearchus, and his assumption that the moon is a mere mixture of air and mild fire, that the air grows dark on its surface, as a ripple courses over a calm sea, and so the appearance of a face is produced.’