纺织英语 第三版 课文翻译lesson four Wool

Lesson FourWoolThe early history of wool is lost in antiquity. Sheepskin, including the hair, was probably used long before it was discovered that the fibers could be spun into yarns or even felted into fabric. There is no evidence to support the theory that wool was the first fiber to be processed into fabric, but it seems certain that, as a part of the skin, wool was used for covering and protection by prehistoric peoples long before yarns and fabrics were made.The earliest fragments of wool fabric have been found in Egypt, probably because of the preserving qualities of the climate. These have been dated from 4000 to 3500 B C. The earliest example of wool fabric found in Europe has been dated about 1500 B C; it was unearthed in archeological digs in Germany. Danish sites have yielded excellent fragments of early wool fabrics dated about 1300 to 1000 BC. These fabrics are rough and coarse and contain considerable wild sheep hair.Wool is a natural fiber of animal origin. Though vegetable fibers were probably the first to be used for spinning and weaving into cloth, animal fibers in the form of skins were the earliest type of clothing worn by man.There are indications that, as early as the seventh century BC, people began to sell and buy woolen goods. The supply of wool available to the world every year amounts to about 5000 million pounds. After scouring, this is reduced to about 3000 million pounds of pure wool. The wool crop is insufficient to meet the world needs. Pure wool is often mixed with other type fibers and recovered wool to meet the demand.The qualities of different wools vary greatly. The merino sheep of Australia, South America and South Africa produce very free and soft wool. The quality of wool from these sources depends upon the conditions and heritage of the sheep. Port Philip wool is the finest in Australia and is used to produce the highest quality woolen and worsted fabrics.Wool from South Africa is very wavy with a good white color and is used for good quality worsted and woolen goods. South American wool is usually of lower quality than wool from Australia or South Africa. Merino wool has been successfully raised in Germany, France, Spain and the United States and is of high quality.To provide the freest-quality wool, production is scientifically controlled. Sheep are inoculated against disease, dipped in chemicals to protect them against insects, and unless on rangeland, fed diet designed to produce healthy animals.Wool can be sheared from the living animal or pulled from the hide after the animal has been slaughtered for its meat. Sheared wool is called fleece or clip wool and is quality to pulled wool, which is taken from the hides of slaughteredsheep Wool considered superiorShearing is currently done very rapidly with power shears. A good worker can completely shear a sheep in less than one minute, sometimes as short as 20seconds. Recent developments in Australia have led to a process called chemical orbiological shearing. The animal is fed a chemical similar to that used in the treatmentof cancer, which cause the hair to fall out within two weeks. Within very short timefollowing the loss of the hair, it starts to grow again, and the sheep suffer no damage.Fibers obtained in this way are slightly longer than those sheared from the animal,and there appears to be less physical damage to the fibers.Usually shearing is done once a year in the early spring, and the fleece is removed in one piece, rolled, packed into bags, and shipped to the nearest processingcenter. Pulled wool is removed from the hide by one of two methods. It may betreated with a depilatory that loosens the fiber and permits it to be pulled away fromthe skin without damaging the hide, or it Can be loosened by the action of bacteria onthe root end of the fiber. Pulled wool is usually mixed with fleece or clip woolbefore processing into yarns and fabrics.Preliminary grading of wool fibers is done while they are still in the fleece, because this step is important in determining cost. Factors used in determining thegrade of wool include fiber fineness or diameter and length, the age of the animal, thenatural color, the breed of the sheep, and the condition under which the animal lived.After grading, fleeces are shipped to the mill, where they are prepared for furtherprocessing into yarns and fabrics.Wool is attacked by hot sulfuric acid and decomposes completely. most other mineral acids of all strengths. Wool will dissolve in caustic soda solutions thatwould have little effect on cotton.第三课羊毛羊毛的早期历史失传了。