Most of the raw silk of commerce is produced in China, Japan, and Italy. It is also produced to a large extent in Italy, Turkey, and Greece, also France and Portugal. The cultivation of silk is not only carried on by private firms, but is encouraged by the government to the extent of granting money to the manufacturers.
Various attempts have been made to raise silkworms in the United States. All have failed on account of the high price of labor necessary to feed the worms.
Throwing. The manufacture in the United States begins with raw silk. We import our raw silk chiefly from Italy, China, and Japan. It is handled here first by the “throwster,” who winds it from the skein and makes various kinds of thread for different purposes.
Raw silk wound on spools in a single thread, and called singles is often used to make warps (that is, the threads running lengthwise of a piece of cloth) for piece-dyed goods, or cloth which is woven with the gum in the silk, and afterward boiled out and dyed. Singles are also sometimes used for filling (that is, cross threads) in very thin fabrics.
Silk yarn that is used for weaving is divided into two kinds, “tram” and “organzine.” Tram silk is made by twisting two or more loosely twisted threads. It is heavier than organzine and is used for filling. Organzine silk is produced by uniting a number of strongly twisted threads. It is used for warp. Crêpe yarn is used in making crêpe, chiffon, and for other purposes. It is very hard twisted thread, generally tram, from forty to eighty turns per inch.
Embroidery silk is made by winding the raw silk, putting a large number of ends together, giving them a slack twist, then doubling and twisting in the reverse direction with a slack twist.
Sewing silk is made by winding and doubling the raw product, then twisting into tram, giving it a slack twist, doubling and twisting in the reverse direction under tension. Machine twist is similar, but three ply.
The principal fabrics made of silk are: silk, satin, plush, chenille, crêpe, crepon, gauze, damask, brocade, pongee, and ribbons. Silk thread and cord are also extensively used. The United States is among the leaders in the manufacture of silk fabrics.
Silk Waste. When the cocoons are softened for reeling a certain portion of the silk is found to consist of waste and broken threads. The tangled silk on the outside of the cocoon is called floss. The residue after reeling, and other wastes in reeling, are known as frisonnets. Floss silk is not used for weaving. It is a slack twisted tram, generally composed of a large number of threads of singles.
Spun Silk. There is another class of threads made from waste silk by spinning and known as spun silk. Waste silks include the pierced cocoons, that is, those from which the moth has come out by making the hole and breaking the fibers in one end of the cocoon; the waste made in the filatures in producing raw or reeled silk, chiefly the outside fiber of the cocoon and the inside next the chrysalis; and also the waste made in manufacture. The waste silk is ungummed; that is, the gum is removed from the fibers by boiling with soap, by macerating or retting, or by chemical reagents.