Suzanne Roberts, age 10, of Bellevue, Wash., for her question:
How is silk made?
The chinese claim that the secret of making silk was discovered by the empress lotan in the year 2697 b.c. for 4000 years the chinese kept the secret to themselves. Then two byzantine monks went spying. They solved the mystery of silk making and returned to europe to prove it with, of all things, a small cache of insect eggs hidden in a staff.
Most silk it spun and twisted into long threads in a textile mill. Other textile machinery weaves the threads into silken fabrics of many kinds. But most of the silk making work is done by an army of hungry caterpillars. In fact, real silk can be created only by these grubs of the silkworm moth. The little white eggs of the silkworm moth hatch into caterpillars. Later the grubs wind themselves in silken cocoons and 81eep through a pupa stage. All fabrics of real silk are woven from these silkworm cocoons.
The job of raising the insects is called sericulture. Since it is not hard work, it can be done by women, children and older people. But the silkworm caterpillar is one of the fussiest creatures in captivity, and sericulture calls for plenty of patience. The little grubs are almost always famished, but they will eat only mulberry leaves and then only slightly wilted mulberry leaves picked fresh every day.
In one ounce there are about 40,000 little silkworm eggs that soon hatch into 40,000 miniature grubs. If all goes well, each caterpillar will molt four times, shedding his old skin for a larger one to cover his growing body. After 30 days the grubs spin their silken cocoons, planning to snooze for two weeks and hatch into adult silkworm moths. In their month of banqueting, the little wrigglers eat a whole ton of mulberry leaves. Their cocoons weigh about 130 pounds, and their soft blankets can be used to yield 12 pounds of raw silk.
Each caterpillar weaves his cocoon from a single thread about half a mile long. He attaches himself to a stick and winds the thread around himself in figures of eight. After 13 days he would give off an alkaline juice to disso1ve an escape hatch in one end of the cocoon. This would break the long single thread into short strands. So the harvest of cocoons is heated to destroy the living insects inside the silk. When the threads are unwound onto reels, they become the raw silk which is sent to the textile mills to be woven into silken fabrics.
China, where the secrets of silk making were first discovered, remains one of the world's sericulture nations. But even more sericulture is carried on in the busy little country of Japan. Italy and some of the South American countries also produce raw silk. Sericulture was tried without much success in the United States however, this country has the mills, the machinery and the industrial skills to change rough, raw silk into fine finished fabrics.