Silk a Brief Description

 Silk a Brief Description

Thousands of years have passed since China first discovered silkworms. Nowadays, silk, in some sense, is still some kind of luxury. Some countries are trying some new ways to make silk without silkworms. Hopefully, they can be successful. But whatever the result, nobody should forget that silk was, still is, and will always be a priceless treasure.

It is well known that silk is discovered in China as one of the best materials for clothing - it has a look and feeling of richness that no other materials can match. However, very few people know when, where or how it is discovered. It could date back to the 30th Century BC when Huang Di (Yellow Emperor) came into power. There are many legends about the discovery of silk; some of them are both romantic and mysterious.

Silk is one of the oldest fibers known to man. Its discovery as a wearable fibre is credited to Lady Xi Ling Shi, the 14-year-old bride of Emperor Huang Ti, the so-called 'Yellow Emperor'. One day in 2640 BC, according to Confucius, she was sitting under a mulberry tree, drinking a cup of tea into which a silk cocoon fell from above. She noticed the delicate fibers start to unravel in the hot liquid and has been credited as the first person to 'reel' or unravel a silk cocoon and use the filament to create a yarn for weaving. Whether or not the legend holds, it is certain that the earliest surviving references to silk production place it in China and that for nearly 3 millennia, the Chinese had a global monopoly on silk production.

One legend has it that once there lived a father with his daughter, and they had a magic horse, which could not only fly in the sky but also understand human language. One day, the father went out on business and did not come back for quite some time. The daughter made him a promise: If the horse could find her father, she would marry him. Finally, her father came back with the horse, but he was shocked at his daughter's promise.

Unwilling to let his daughter marry a horse, he killed the innocent horse. And then a miracle happened! The horse's skin carried the girl flying away. They flew and flew, at last, they stopped on a tree, and the moment the girl touched the tree, she turned into a silkworm. Every day, she spit long and thin silks. The silks just represented her feeling of missing him.

Another less romantic but more convincing explanation is that some ancient Chinese women found this wonderful silk by chance. When they were picking fruits from the trees, they found a special kind of fruit, white but too hard to eat, so they boiled the fruit in hot water, but they still could hardly eat it. At last, they lost their patience and began to beat them with big sticks. In this way, silks and silkworms were discovered. And the white hard fruit is a cocoon!

The cultivation of the silkworm is known as 'sericulture.' The tiny eggs of the silkworm moth are incubated until they hatch into worms when they are placed under a fine layer of gauze covered with finely chopped mulberry leaves. For six weeks the caterpillars (silkworms) eat almost continually, reaching a length of roughly 75mm. Branches are placed in their rearing houses at the end of this period, which the silkworms will climb to build their cocoons in one continuous length of silk filament. Liquid secretions from two large glands in the insect emerge, which harden exposure to the air and form silk.

Silk is an animal fibre produced by silkworm insects to build their cocoons. Although many insects produce silk, only the filament produced by the mulberry silk moth, Bombyx mori, and a few others in the same genus, is used by the commercial silk industry. The silk produced by other insects, mainly spiders, is used in a small number of other commercial capacities, for example, weapons telescope crosshairs and other optical instruments. 

Silk filament comes from the cocoons built by 'silkworms,' which are not worms at all, but silk moth pupae. If allowed to hatch, the silkworm moth has a lifespan of up to three days. The moths do not eat. They rarely fly and reach a wingspan of 40 - 50mm with a thick hairy body. The female lays 300 - 500 eggs in that time.

The raising of silkworms and unwinding cocoons is now known as silk culture or sericulture. It takes an average of 25-28 days for a silkworm, which is no bigger than an ant, to grow old enough to spin a cocoon. Then the farmers pick them up one by one into piles of dry straws. Mostly, the silkworm will attach itself to the straw, with its legs to the outside and begin to spin.

Over three days, the silkworm spins its cocoon, producing up to 950 meters of silk filament. If the moth were allowed to hatch, the silk strands would be broken. They are preserved intact by killing the pupa before it hatches with hot air or steam. The silk is then unbound from the cocoon by softening the sericin and then delicately and carefully unwinding, or 'reeling' the filaments from 4 - 8 cocoons at once, sometimes with a slight twist, to create a single strand. The amount of usable silk in each cocoon is small, and about 5500 silkworms are required to produce 1 kg (2.2 lb.) of raw silk.

The next step is unwinding the cocoons; it is done by reeling girls. The cocoons are heated to kill the pupae. This must be done at the right time, otherwise, the pupas are bound to turn into moths, and moths will make a hole in the cocoons, which will be useless for reeling. To unwind the cocoons, first put them in a basin filled with hot water, find the loose end of the cocoon, and then twist them, and carry them to a small wheel, thus the cocoons will be unwound. At last, two workers measure them into a certain length and twist them, they are called raw silk, and then they are dyed and woven into cloth.

'Raw silk' is silk that still contains sericin. Once this is washed out (in soap and boiling water), the fabric is left soft, lustrous, and up to 30% lighter! The thickness of silk filament is expressed in terms of denier - the number of grams of weight per 9000 meters. Spun silk is given a numerical designation based on the number of hanks (840yd lengths) per pound. 

Silk filament is strong, as strong as steel of the same thickness, resisting breakage up to a weight of 4g per filament, and much stronger than cotton or wool. Silk is also lower in density than cotton, wool, or nylon and as such, is highly moisture absorbent, able to absorb as much as a third of its weight in moisture without feeling damp. Silk loses strength over time if kept in bad storage conditions and weakens eventually if constantly exposed to strong sunlight (eg curtains). 

An interesting fact is that we can unwind about 1,000 meters long silk from one cocoon, while 111 cocoons are needed for a man's tie, and 630 cocoons are needed for a woman's blouse.

Chinese people developed new ways of using silk to make clothes since the discovery of silk. This kind of cloth called silk became popular soon. At that time, China's technology was developing fast. 

The Chinese realized the value of the beautiful material they were producing and kept its secret safe from the rest of the world for more than 30 centuries. Travellers were searched thoroughly at border crossings, and anyone caught trying to smuggle eggs, cocoons, or silkworms out of the country was summarily executed. Demand for this exotic fabric eventually created the lucrative trade route now known as the 'Silk Road,' of which mention is made as early as 300BC in the days of the Han Dynasty, taking silk westward and bringing gold, silver, and wools to the East.  Soon, the Emperor of the Han Dynasty decided to develop trade with other countries.

Building a road becomes a priority to trade silk. After nearly 60 years of war, the world-famous ancient Silk Road was built at the cost of many losses of life and treasures. It started in Chang'an (now Xi'an), across Middle Asia, South Asia, and West Asia. Many countries in Asia and Europe were connected. The Silk Road began at Sian and was some 4,000 miles long. A caravan tract, it followed the Great Wall of China.

Few people travelled the entire route - goods were handled mostly by a series of middlemen. With the mulberry silk moth native to China, the Chinese had a monopoly on the world's silk production until about 200 BC when Korea saw the emergence of its silk industry thanks to a handful of Chinese immigrants who had settled there. The secret was out. Eventually, other countries began to produce silk too, India and Japan being the first to do so in about AD 300. Silk had become a valuable commodity in the Western world and in 550AD Emperor Justinian I sent two Nestorian monks to China to smuggle back some moth eggs and mulberry seeds, which they did at the risk of their lives, concealing the precious goods in bamboo walking staffs. With the arrival of the silk eggs in Byzantium, China's silk monopoly was at an end.

From then on, Chinese silk passed to Europe. Romans, especially women, were crazy about Chinese silk. Before that, Romans used to make clothes with linen cloth, animal skin and wool fabric. Now they all turned to silk. It was a symbol of wealth and high social status for them to wear silk clothes. One day, an Indian monk came to visit the emperor. This monk had been living in China for several years and knew the method of raising silkworms. The emperor promised a high profit for the monk, the monk hid several cocoons in his cane and took it to Rome. Then, the technology of raising silkworms spread out.

The ancient Persian courts did not know how to make their silk, would untie Chinese silks and reweave them into Persian designs which were so beautiful that when Darius III, King of Persia, eventually surrendered to Alexander the Great, he was clothed in such silken splendour that he completely outshone Alexander, who promptly demanded as spoils of war the equivalent of £11 million in silk.