Likewise, the blend of vinegar and honey becomes neither vinegar nor honey, for each of the two has departed from its own nature. The same applies to an alloy of gold and silver: it is no longer sound, being neither true gold nor true silver; and the mixture of silver and copper is likewise unsound, neither silver nor copper. This, then, is one of the three modes.
The second mode is a “mixture-in-separation” of two heavy substances, each of which can still be identified within the other, retaining its own substance and form—such as oil and water in a single lamp, linen and silk in one garment woven of linen and brocaded with silk, or a copper idol whose head is gold. None of these should properly be called a mixture, because the two natures and substances remain distinct, just as no one would speak of a mixture between water and the qullah (earthenware jug) that contains it: the jug is clay, its substance that of a jug, and between it and the water there is the sharpest separation.
In the same way, oil and water would never come together were it not for the vessel of the lamp that confines them; linen and silk share no mixture even though they are in a single robe; nor do gold and copper when they have not been fused together, even if one statue unites them.
These two supposed mixtures occur only among dense, heavy bodies. But if some of them are actually fused—such as when gold and copper are melted and poured together—the result falls under the first mode, the mixture of transformation and corruption, for that ingot is neither sound gold nor sound copper.