Then the Empress asked them the reason, why the sun and moon did often appear in different postures or shapes, as sometimes magnified, sometimes diminished; sometimes elevated, otherwhiles depressed; now thrown to the right, and then to the left? To which some of the Bird-men answered, that it proceeded from the various degrees of heat and cold, which are found in the air, from whence did follow a differing density and rarity; and likewise from the vapours that are interposed, whereof those that ascend are higher and less dense than the ambient air, but those which descend are heavier and more dense. But others did with more probability affirm, that it was nothing else but the various patterns of the air; for like as painters do not copy out one and the same original just alike at all times; so, said they, do several parts of the air make different patterns of the luminous bodies of the sun and moon: which patterns, as several copies, the sensitive motions do figure out in the substance of our eyes.