[Illustration: MICROSCOPIC APPEARANCE OF WOOL FIBERS]
The great value of wool as a fiber lies in the fact that it is strong, elastic, soft, very susceptible to dye stuffs and being woven, furnishes a great number of air spaces, rendering clothing made from it very warm and light.
Climate, breed, and food influence the quality of the wool. Where the pasturage is barren and rocky, the wool is apt to be coarse.
The Variety of Sheep Giving the Finest Wool.]
There are supposed to be about thirty distinct varieties of sheep, nearly half of which are natives of Asia, one-third of Africa, and only four coming from Europe, and two from America. Wool is divided into two general classes--long and short staple, according to the average length of fiber. The long fiber wool is commonly carded, combed and spun into _worsted_ yarn. The short fiber is usually carded and spun into woolen yarn. The short fiber obtained in combing long staple wool is called "noil." It is used for woolens.
Alpaca, Vicuna and Llama wools are obtained from animals which are native to the mountains of Peru and Chile. The Angora goat, originally from Asia Minor, furnishes the mohair of commerce. This fiber does not resemble the hairs of common goats in any respect. It is a very beautiful fiber of silky luster, which constitutes its chief value.
The fur of beavers and rabbits can be and is used in manufacture, either spun into yarn or made into felt. The fibers of both animals enter largely into the manufacture of felt hats.
The fleece of sheep after being sheared is divided into different parts or _sorted_, according to the quality of the wool, the best wool coming from the sides of the animal.
_a_--Medium Wool; _b_--Camel's Hair; _c_--Diseased Fiber; _d_--Merino Wool; _e_--Mohair.]
As it comes from the sheep, the wool contains many substances besides the wool fiber which must be removed before dyeing or spinning. This cleansing is called _scouring_. Before scouring, the wool is usually dusted by machines to remove all loose dirt. The scouring must be done by the mildest means possible in order to preserve the natural fluffiness and brilliancy of the fiber. The chief impurity is the wool grease or "yolk" which is secreted by the skin glands to lubricate the fiber and prevent it from matting.