Book III about halite and nitrium, alum and acrid juices and related minerals, sulphur, bitumen, realgar, and orpiment; the fourth, chrysocolla, aerugo, caeruleum, ferrugo

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	BOOK III	47

	placed on live coals or in earthenware vessels over a fire it dries and swells into bubbles similar to nitrum and loses some of its substance.¹³ Like other congealed juices it is soluble in water; the spherical, bubble-like variety dissolving the most rapidly. Alum is used by goldsmiths, dyers, copyists and physicians. Goldsmiths clean gold with it and use it when covering copper with gold leaf. Dyers prepare their wool as well as cloth by washing it in water in which alum has been dissolved. Wool or cloth, so treated, takes the dye easily and retains the color for a long time. When the wool is to be dyed a light color they use the white liquor and when dying wool black they use the cloudy or dark liquor, according to Pliny. Today dyers always use the white mineral since they do not have the natural liquors. The mineral is also used when they dye hides. Leaves of books that are dipped in water in which alum has been dissolved become strong and tough and can be written on with inks that are acid without having the ink sink into the paper as is often the case with untreated paper. When used as a medicament, alum has a drying power, drawing together ulcers and wounds. According to Dioscorides, in the olden days they used the broken, nodular, and liquid forms. The rough, cleavable material is the best of all, especially that from Egypt which is pure, fresh, white, and strongly astringent. The best nodular material is the native mineral which intumesces into bubbles when pure. This usually comes from Melos or Egypt and is pale white, moderately unctuous, soft, and strongly astringent. The best liquid is that which is the color of milk, translucent, and with the odor of fire. I shall now take up the juice the Latins call atramentum. Since there are three kinds of atramentum and the name of each comes from the black color, it has been named sutorium to distinguish it from librarium and metallicum because it is used by both the shoemaker and leather worker to dye leather black. It is called χάλκανθος by the Greeks because it forms as an efflorescence on copper.¹⁴ Cupriferous pyrite, which is also called ckalcitis, is the parent and source of sory, and melanteria which is also called atramentum metallicum. These minerals, in turn, produce atramentum sutorium and other closely related minerals.¹⁵ This can be seen especi- ¹³ Alum contains approximately 45.6% water and 13.5% sulphur. ¹⁴ From χαλκό?, brass or copper, and άνθος, a flower. ¹⁵ De Ortu et Causis Subterraneorum, Book I, page 13, "When moisture corrodes cupriferous and friable pyrite it produces an acid juice from which atramentum sutorium forms and also liquid alum." Idem, Book III, page 46, "When water has covered pyrite it produces atramentum sutorium either through being congealed by cold or evaporated by heat." Idem, Book III, page 47, "Not only are atramentum sutorium and alum made from an acid juice but also sory, chalcitis, and misy. Misy is "flowers" of atramentum sutorium just as sory is "flowers" of melanteria. Experiments show that when porous, friable pyrite is attacked by moisture such an acid juice is produced. Green atramentum sutorium in the form of hairs very often appears on this kind of pyrite together with melanteria which covers the pyrite."

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