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Outline:
Introduction
A- Facts :
-History of silk .
-Silkworms life cycle
.
-Silk processing.
B- Analysis.
Conclusion.
Introduction
Since his existence, man has been discovering Mother Nature's treasures. His relationship with those treasures can be defined as a constantly evoluting one with a urde diversity that enabled him experience and accumulate knowledge through the years.
This knowledge has certainly begun with a first time discovering that raised many questions in man’s mind. One important discovery is the discovery of silk. One classmate told me that: “you still have time to change the subject of your speech”.
The object she meant was how to raise silkworms. This essay will
inform its readers on the history, cultivation and processing of silk.
History of silk
No one knows for sure when silk was discovered according to a Chinese legend, about 2700 B.C. in the garden of Emperor Huandgi. The Emperor ordered his wife, Xilingshi, to find out what damaging his mulberry trees.
Xilingshi found white worms eating the mulberry leaves and shining shiny cocoons. She accidentally dropped a cocoon into hot water. As she played with the cocoon in the water, a delicate, cobwebby tangle separated itself from the cocoon. Xilingshi drew it out and found that one sleader thread was unwinding itself from the cocoon. She had discovered silk.
Xilingshi persuaded her husband to give her a grove of mulberry trees, where she could grow thousands of worms that spum such beautiful cocoons. It is said that Xilingshi invented the silk reel, which joined these fine filaments into a thread thick and strong enough for weaving. Some stories also credit her with inventing the first silk loom.
No one knows how much, if any, of this story is true but his torians do know that silk was first used in China, the Chinese guarded the secret of the silkworm. Disgrace and death faced the traitor who disclosed the origin of silk to the outside world. Only the Chinese knew how to make silk for about 3’000 years. China carried on a profitable silk trade with western nations in the days of the Man Dynasty (founded in 202 bc) Traders from ancient Persia bought richly colored silks from Chinese merchants.
Camel caravans blazed routes across Asia, transporting silk from China to Damascus, the market place at which east and west met. From Damascus, silk was taken to the Roman empire, where there were riches to exchange for it.
As early as the 3’000 B.C., the western world heard rumors of the strange worm that spum silk threads. But no one in the west saw the worm until about A.D. 550. All the time, Persia controlled all silk that came out of China. Persians sold it at fabulously high prices. The Roman, or Byzantine, emperor Justinian objected to paying high prices to the Persians. He sent two manks to China as spies. Risking death, the monks smuggled out silkworm eggs and mulberry seeds in follow bamboo canes. This adventure ended the Chinese and Persian silk monopolies.
During the next few hundred years various peoples learned how to raise silkworms and take silk from the cocoons the muslins brought silkworms to Spain and Sicily in the 800’s and 900’s. By the 1200’s, Italy had become the silk center of the west. Silk weaving became an important industry in England after a large number of skilled flourish weavers entered the country in the late 1500’s. The first silk factory in the USA was built in Mansfield in 1810.
This historical overview has chronologically stated the spread of
silkworms into civilizations that learned how to raise the silkworms.
Silkworms life cycle
The raising of silkworms requires a great deal of care and patience. Silk farmers treat the Bomby mori as carefully as they would a newborn baby. They raise it under carefully controlled temperatures. They protect it from mosquitoes, flies, and other insects. The Bombix mori –name of the silk worms- has life cycle divided into four stages ending by a metamorphosis: eggs, silkworms, cocoons pimming and metamorphosis into a mooth (butterfly).
In early summer, a female Bombyx mori lays from 300 to 500 eggs. It deposits them on special strips of paper provided by the silk farmer. The moth dies soon after it lays its eggs. The eggs undergo many tests to make sure they contain perfect disease-free worms. Then they are put in cold storage. Early, the nest spring, the silk farmer puts the eggs in an incubator. An incubator is a device for keeping the eggs at a suitable temperature for hatching. About 20 days later the eggs hatch into tiny silkworms have.
The young silkworms are put on trays that are kept spotlessly clean to prevent disease. At first, the silkworms have enormous appetites. They eat almost continually, both night and day. The silkworm’s supplies then with fresh mulberry leaves every two or three hours. The worms grow to about 70 times their original size and shed their skins four times.
After 4 to 5 weeks, the silkworm is about 3 inches long and nearly 1 inch thick. Its body has 12 sections and three pairs of legs.
When finally grown, the silkworm stops eating and is ready to spin its cocoon. The worm creeps into a tiny wooden compartment containing twinges or steams of straw that the farmer has prepared. The worm spins a net or web to hold itself to a twig or stem. It then forms a cocoon, which is the silk. To do this it swings its head from side to side in a series of figure-eight movements. Two glands near the silkworm’s lower jow give off a fluid that hardens into fine silk threads as it hits the sericin. The sericin cements the two threads of silk together.
The silkworm spins the silk around and around its body, until all
the fluid has been used. After about 3 days of spinning, the cocoon is
completed. The worm changes into a pupa, which is the third stage of its
life cycle. It permitted to live, the pupa becomes a moth in about three
weeks, this completing the life cycle, a metamorphosis when a pupa changes
into a moth, it bursts the cocoon and breaks the long silk thread into
many short ones. For this reason, silk farmers allow only a small percentage
of pupas to develop into moths. These moths are kept to lay the nest batch
of eggs to save silk, the other insects are killed before they break their
covering. Silk farmers usually kill the insects by placing the cocoons
in a hot oven the silkworms are now dead but the story doesn’t end. It
is now the time to process the silk cocoons into beautiful and useful end-products.
Silk processing
Processing the silk begins by reeling, throwing, boulugoff and weighting, dying and weaving.
Reeling: after the pupa has been killed, silkworkers are ready to reel (unwind) the long delicate threads of the cocoon this is done in a reeling factury called a “filature”. The cocoons are soaked in bassins of hot water to dissolve the gummy sericin that holds the threads together. Threads from several cocoons are unwound at the same time, because a single filament is far too fine to be reeled separately. As the cocoons bob about in the basin, their filaments are drawn together and peeled by pulleys through a tiny porcelain guide. The guide is much like the eye of a needle.
The melted sericin glues several silk filaments into a single thread,
which is wound onto a reel. Later, the silk is removed from the reel and
twisted into skeins. Fifteen double skeins. Fifteen double skeins or 30
small skeins are bound into a larger bundle called a book. A bale of raw
silk ready to be shipped to a unit for weaving contains about 30 books
and weighs about 135 pounds throwing: the raw silk is now much stronger
than it was when it left the cocoon. But it is still not strong enough
to be woven into anything except the sheerest material. It is strengthened
by a series of processes called throwing. The term comes from the Anglo-Saxon
word threw (Twist). Throwing is increasing the twist or adding strands
and twisting then together.
Boiling off and weighting: when the silk comes from the throwing
machines, there is still too much sericin on it. Workers boil the silk
in a solution of that soap to remove the sericin. The process is called
boiling off, the removal of the sericin uncovers the natural bacteria of
the silk boiled: off silk is usually unlikely white. The sericin can be
removed either before or after weaving, depending on the type of fabric.
Boiling off causes the silk to lose about 25% of its weight.
Dyeing: brilliant dyes may be applied to silk yarn before it is woven. This type of dyeing is called skein dyeing. Some silk fabrics are dyed after they are woven. This process is called piece dyeing.
Weaving: silk yarns are woven on looms much like those used for cotton
and wool. Automatic power looms have replaced hand-weaving methods in almost
all countries. Many silk fabrics, including damasks and heavy evening wear
fabrics, are woven on jacquard looms. Beautiful designs or patterns can
be woven on these looms.
Analysis:
Since the beginnings of time, man have been, and still, interacting with mother nature and its elements in order to dominate it to a certain extent and cherish from all its treasures, that’s why he is called master of the universe.
Mastering the cultivation of silkworms, thus the production of silk, took him a lot of time, effort and resources in order to arrive to the actual level of know how in the production of silk talking about production pushes us to focus on the economical dimensions , of the introduction of silkworms, cultivation in the lebanese economy.
In this section, we will provide the summary of the main issues and problems of the “Lebanese bureau of silk” which is a republic service office located in Kfarchima.
The building is very old, and the physical equipment there is so old and destroyed by the war.
No renovation has been made since then and the reason given by the man in charge there was that the government is not able to allocate financial resources in this field of production because of other priorities.
Nevertheless, some help is coming from external parties which are providing the eggs of the silkworms and some budget nearby able to balance the expenses of the maintenance of the minimal pace of work. Unfortunately, this is a bad sign in the development of the economy. Why?
A country cannot prosper unless all its productions are aiming to
such goal.
The solution is to raise funds in order to restore the building
as well as its physical resources ranging from the least detail till the
very sophisticated machines.
Parallel to such development, a certain effort should be made on the human side. Training sessions as well as more young human resources with the necessary academic background should be bought in order to have “new blood” in the system positive ideas.
Moreover, the government should give some territories to cultivate the mulberry trees, the factory and some houses for the farmer’s family in order to encourage them invest in this field that has been almost dead for a long period of time. If this dream might come true there is still a problem of keeping this production up to date with international standards and controlling the priving issue.
Actually, the price of 1 kg silk cocoons is so cheap because figures are still the same since the beginning of the war.
Adding the inflation factor, the problem is to became worse.
The man in charge at the bureau didn’t reveal the price of the silk for many reasons that he didn’t want to reveal.
The solution to this problem would be to stade an official price
in the stock market of possible so no monopolies would take place to protect
both the farmer and the sector.
Through, the conversation with that person, he staded the main important
regions of cultivation of silkworms which were (Hadad, Beit Chebab, Zouk,
Deir al Kamar, Kfarchima and Jourret el Ballout).
If you visit these regions, you can detect the huge number of mulberry trees but unfortunately they are slowly being replaced by other vegetation providing money to support the living in such difficult times. The best solution to this complicated problems is privatization and the change in the investor’s mind to become silkworms and not averters.
Finally, it is our job to work hard as the silkworm, that work through its life, night and day to reach its final objective it ends its life in the cocoon just to give 500 life in the next season assuring the continuity of its species.
Conclusion:
Silkworms turned to be very important animals with an interesting discovery surrounded by many legends and a history that shaped relationships among civilizations irrespective or being producers or consumers.
Moreover, their life cycle is of great mystery and has raised through the observation many questions that have been answered.
Adding the processing of the raw material into artistic end-products of many uses.
Finally, the generously producing silkworms arises our curiosity
to enlarge our knowledge from the never-ending best seller of mother nature’s
species.
REFERENCES:
Grolier 1996. Silkworms [ cd.rom].
Microsoft, encarta, 1998- silkworms [cd.rom]
Grand Larousse en 10 volumes, 1995.
TEST:
1-Acording to a Chinese legend , who discovered silk ? And when?
2-What are the lifecycle four stages of the Bombix Mori ?
3-What is an incubator ? Why does the farmer use it?
4-How many times do worms shed their skin?
5-When does the moth die ?
6-How do farmers kill the pupas ?
7-Put in order the different stages of silk processing.
8-What is the sericin ?
9-What is the difference between skin dyeing and piece dyeing ?
