Wool is the fleecy covering of sheep. It is distinguished by its waviness and the scaly covering of the fibers. The scales are more pointed and protrude more than those of hair. This gives it a tendency to mat or felt. The waviness of wool is due to the spiral structure of the fibers. Next to cotton, wool is the most extensively used of all the textile fibers.
The Romans developed a breed of sheep having wool of exceeding fineness, and later introduced their sheep into Spain. Here they were still further improved, and it was not many years until Spain led the world in the production of wool. The fine wooled Merino sheep originated here. Australia and the United States are also great wool-producing countries.
There are three classes of wool, classified according to the length, fineness and felting qualities:
1. The carding or clothing wool.
2. The combing or worsted wool.
3. The blanket or carpet wool.
Wool on different parts of the same animal varies greatly, that on the shoulders being the finest and most even. All unwashed wool contains a fatty or greasy matter called yolk or suint. This keeps the fiber from matting together and also protects the fleece from injury. The yolk must be removed before the wool is manufactured into cloth. When the fleece is cut from the body of the sheep it sticks together so that it can be spread out like the hide of an animal, and each fleece is tied in a separate bundle. A few years ago sheep shearing was done by hand. This was a busy time, especially on large ranches where thousands of sheep were to be sheared and it required a large crew to do the work. It is now accomplished with much less time, labor and expense by machinery.
Alpaca and Mohair are classed as wools, but the former is produced by the Alpaca goat and the latter by the Angora goat. Cashmere wool comes from the Cashmere goat, found in Thibet, and is very costly, as only the finest parts of the fleece are used. In the far eastern countries beautiful, costly fabrics are made from the long hair of the camel.
When wool comes to the factory in the raw state it must be scoured. This is done by passing it through machines containing strong soap suds, and afterwards rinsing it. After the wool is dry it is mixed or blended. Mixing is an operation of great importance and is done to make the wool of uniform quality. Portions of wool from different lots, qualities and colors are placed in alternate layers and blended. If it is desired to mix other materials with the wool, such as silk, cotton or shoddy, it is added at this time.
The wool is harsh to the touch after it has been scoured, owing to the removal of the yolk. To restore its natural softness it is slightly sprinkled with oil during the process of mixing.
The process of carding produces a thread having fibers projecting loosely from the main thread in little ends which form the nap of the finished cloth. After it is carded it is wound on spools and is ready for the spinning. In spinning the threads are held together by their scales and the waviness of the fiber which prevents them from untwisting. Another valuable feature of wool is its elasticity, which makes it soft to the touch and this is retained in the manufactured goods.