The rug wools grown in Persia, Turkestan, Turkey in Asia, and the Caucasus Mountains are also characteristic. They vary in fineness, and because they do not readily felt they are the best in the world for rug stock. The "pile" or surface of the rug remains elastic and stands upright even after a hundred years of wear. This quality is due mainly to conditions of climate and soil. [Illustration: WOOL PRODUCTION] In some instances the wool is obtained by a daily combing of the half-grown lambs. This process, however, is employed in the rug-making districts only; in general, the fleeces are clipped either with shears or machine clippers. In the United States the latter are generally employed, and but little attempt is made either to sort the fleeces or to separate the various qualities of wool in the same fleece. The raw wool always contains foreign matter such as burs and dirt; it is also saturated with a natural oil which prevents felting. The oil, commonly called "grease," or "yolk," is an important article of commerce; under the name of "lanolin" (_adeps lanae_) it is used in medicine and pharmacy as a basis for ointments. The world's yearly clip is a little more than two and one-half billion pounds, of which the United States produces about one-eighth. In Europe and the United States, owing to the increasing value of the land, the area of production is decreasing; in Australia, South Africa, and Argentina, where land is cheap, it is increasing. From these three regions wool is exported; most European countries and the United States buy it. In the latter country the consumption is about six pounds for each person. [Illustration: WOOL] The wools of the Mediterranean countries--France, Spain, Italy, Algiers, Egypt, etc.--are the best for fine cloths; those of central Asia for rugs and shawls; the others are used mainly in medium and low grade textiles. =Other Wools.=--The Angora goat, originally grown in Anatolia (Asia Minor), and the Iran States (Persia, Afghanistan, and Baluchistan), furnishes a beautiful white wool, commercially known as "mohair." Smyrna is an important market for it, and England is the chief buyer. The Angora goat has been introduced into South Africa and California, where it is successfully grown. From the former country there is a large export of mohair. Cashmere wool is a fine, downy undercovering, obtained by combing the fleece of a goat native to the Kashmir Valley in India. A single animal yields scarcely more than an ounce or two, and the best product is worth about its weight in gold. It is used in the manufacture of the famous Cashmere shawls, which are sold at prices varying from five hundred to five thousand dollars. They are made in Persia and India.