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Here Apollonides, taking up the discourse, said: Tell me then, I beseech you, good sir, even by the moon herself, do you think it possible that there should be there shadows of caves and chinks, and that the sight of them should come even to our eyes? Or do you not regard what will come of it? And must I tell you what it is? But hearken to me, although you are not ignorant of it. The diameter of the moon, according to that bigness which appears to us when she is in her mean and ordinary distances, is twelve digits, and every one of these black and shady spots is above half a digit, that is above the four and twentieth part of the diameter. Now if we suppose the circumference of the moon to be only thirty thousand stadia; and the diameter according to that supposition to be ten thousand, every one of these shadowy marks within her will not be less than five hundred stadia. Consider then, first, whether there can possibly be in the moon such great gaps and such inequalities as may make such a shadow? And then how is it possible that, being so great, they are not seen by us?