英文科學(xué)讀本 第五冊·Lesson 53 Cotton

Lesson 53 Cotton

Cotton supplies materials for clothing man in all parts of the world—indeed, it clothes more individuals by far than any other material, and may thus justly take its place among the most abundant and most important of all materials used for textile goods. It provides not only calico and print, muslin, lace, hosiery, and similar materials of light texture, but also heavy stout materials fit for men's wear, such as corduroy, moleskin, fustian, velveteen.

We dealt with some of its properties as a clothing material in our lessons on heat. Among its other properties it is soft and easily worked; it is warm to the touch, although very light, and when dirty it can be easily washed.

This valuable product is obtained from the seed-pod of the cotton plant. In the pod the seeds are packed in a soft, white, downy wool. This is the raw cotton of commerce—the material from which all our cotton fabrics are made.

There are several varieties of the cotton plant. One kind, which is cultivated chiefly in India and China, is a tree, and grows to the height of nearly 20 feet; another is a small woody shrub, about the size of an ordinary currant-bush. The plant which supplies almost all the cotton of commerce is an annual or herbaceous plant, which grows from seed sown every spring, comes to perfection and ripens, and dies down in the autumn.

This plant is cultivated largely in the United States, West Indies, Natal, Egypt, Queensland, and in almost all the warmer parts of the world. Provided only that the climate be dry and warm, it will succeed in soils too poor for the production of almost any other crops.

Its leaves are of a rich dark-green, and it bears large, bright-yellow flowers, with a purple spot in the center, not unlike our hollyhock. When the flower dies it leaves behind a triangular-shaped pod about the size of a walnut. The seeds which it contains are embedded in the mass of cotton wool. They are about the size of the seeds of a grape. When pressed they yield oil and oil-cake. When the plant is fully ripe the pods burst, owing to the swelling of the woolly matter which they contain. It is then time to gather in the crop. The cotton is picked in the autumn by women and children, who go through the plantation, from plant to plant, with bags or baskets slung round their necks.

As the pods are plucked, the wool and seeds are removed together, and carried away in baskets to be dried in the sun. When they are quite dry, the first part of the work of preparation begins by the separation of the seeds from the woolly down. This is done by a machine called a gin.

There are several varieties of gins. That used in America is the best. It consists of a sort of box, the bottom of which is formed of strong parallel wires, about one-eighth of an inch apart. Between these wires a number of circular saws project upwards into the box, which is loosely filled with the newly-picked cotton. The saws are made to revolve by machinery and, as they turn, their teeth drag the cotton through the bars, leaving the seeds behind. Some of the seeds are saved for next spring's sowing; the greater part are crushed for the oil which they contain.

The cotton, thus freed from its seeds, is pressed by powerful machinery into great bales, each bale weighing about 350 lbs., and is then ready to be shipped to the manufacturer. The raw cotton is not all of the same quality. One kind, which is more highly prized than all others for the length and strength of its fiber, is known as long staple. Its fibers are usually about an inch and a half long. The best variety of the long staple is that known as Sea Island Cotton. It takes its name from the fact that it was first grown, and is still grown to greatest perfection, on the islands lying off the shores of Georgia, the soil of which is rich alluvium. In the commoner sorts, known as short staple, the fibers do not exceed three-quarters of an inch in length.