9I now return to the preparation of vermilion. When the clods are dry, they are pounded and reduced to powder with iron beaters, and then, by means of repeated washings and dryings, the colour is produced. When this is effected, the vermilion, deprived of the quicksilver, loses its natural tenacity, and becomes soft and disconnected; and used in the last coat of the plastering of rooms, keeps its colour without fading.
9I will now return to the preparation of vermilion. When the lumps of ore are dry, they are crushed in iron mortars, and repeatedly washed and heated until the impurities are gone, and the colours come. When the cinnabar has given up its quicksilver, and thus lost the natural virtues that it previously had, it becomes soft in quality and its powers are feeble.