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	28	DE NATURA FOSSILIUΜ

	clean cloth. Only fullers use these earths for cleaning. Some fullers, limited by the unctuousness of their earths, add soap believing that this will increase their cleansing power. Many of these earths derive their names from islands and countries. Cimolia earth, also called Smectis earth because it cleans so well, comes from Cimolus, one of the Cyclades islands; Sarda earth, from Sardinia; Umbrica earth from Umbria. Only the earths from these localities are of value. They are used in the following manner. If the cloth is colored it is washed first in a vessel with soap and Cimolia or Umbrica earth. Theophrastus writes that instead of Cimolia earth the Greeks used gypsum from Tymphrestus. The cloth is then fumigated with sulphur. Finally it is again cleaned with Cimolia earth. If the cloth is white, instead of Cimolia or Umbrica earth, they use Sarda, then fumigate with sulphur and accomplish the final cleaning by beating the cloth on a rock. Fuller's earths are found today in many parts of Germany, for example, Fulda in Alsace; two varieties, one white similar to tufa, the other gray, at Hildesheim, Saxony; a gray earth at Cadan, Bohemia; a lighter gray earth at Leipzig, Misena. The color of the earth is of no importance, the primary property being the power to remove grease from cloth. According to Galen fullers used one of the three genera of Lemnia earths. It is seen that any unctuous, acrid earth which is not hard can be used by a fuller. Painters use meager, intermediate, or slightly unctuous earths, the most unctuous being called Paretonium. It does not matter if the earths are porous, intermediate, or dense but they prefer the soft or intermediate varieties since the hard earths require too much work to prepare them. All must be crushed fine. Although they use those which are moist they prefer the dry since these are easier to prepare. Painters are the only artisans who select earths on the basis of their color. Some are white such as the chalk from Paretonium, Melos, and Eretria. Ochers may be various shades of red and yellow. Some earths, commonly found in mines, are realgar-red. Chalk may be green or black. Other earths are found with many different colors. Similar earths are used by carpenters, for example, red ocher, green, and black chalk. Carpenters can use any color except white since a white fine is not readily visible on white wood. Other artisans prefer meager or porous earths which are either soft or intermediate and somewhat acrid. Hard earths are of little value. Silversmiths use a clay² called argentaria for cleaning silver. The name is derived from its use by silversmiths. The earth used by barbers is called tripela? It is used to clean the brass vessels in which they keep the warm water and soap used in washing and shaving. This same earth is used to polish armor and gems. It is yellowish in color and harsh to the touch. Other earths used for polishing and cleaning may ² Agrioola uses the word creta, the name usually applied to chalk. However, since chalk is harder than silver it is doubtful if it would be used to clean it. ³ A German corruption of the latin spelling, tripolis.