Wednesday, April 30, 2008

Sericulture

Like so much else involving technology in the ancient world, the origins of silk cultivation are hotly debated and kind of foggy. The Chinese, in typical fashion, attribute the invention to a mythical figure - the wife of the Yellow Emperor, Lady Hsi Ling Shih - and have an exact date, 3000 BCE. Which sounds kind of wild, that it goes back that far, but I tend to believe the Chinese, at least in the sense that their mythic stories are very likely based on something that really happened. (And silk WAS invented, in China. It's just the date that people argue over. So they got that right.)

But wait. It gets better. In recent decades, archeologists have found all sorts of silk-related artifacts, from actual tools for sericulture to carved decorations portraying silk worms. And some of them have been dated as far back as 5000 BCE.

So. In a nutshell, sericulture has been going on a hell of a long time.

In addition to having an impressively ancient history, sericulture in China is notable for another reason; they managed to keep it secret for THOUSANDS of years. Even after they began exporting it, no one outside China knew exactly what it was. Pliny, the Roman historian, wrote in 70 BCE that silk was made from fur off leaves. (??!??) Sericulture didn't make it to Europe until the later crusades, around 1200 CE. Silkworms had made it as far as Byzantium, and during the crusades, Euros stole the idea.

The technology - and bugs - needed for silk production first traveled to Korea, in about 200BCE, taken by Chinese settlers who were colonizing the area. There was commercial silk cultivation done with smuggled worms (ha), in India by 300 BCE. After that it moved slowly westward - as each civilization learned the method, they attempted again and again to keep it secret, so as to control the market.

Silk, history's best-kept secret.

Anyway, here's how it works. (People have been gathering 'wild' silk for thousands of years in SE Asia, simply picking cocoons off trees and processing them much like the domestsic version.)

The domesticated silk worm, Bombyx mori, is dumb as a rock. It's been bred that way. Blind, unable to fly, all it does is eat mulberry leaves (the only food it will eat), make more silkworms, and spin about 900 yards of silk filament to make its cocoon. They're born pregnant, like tribbles. It will lay about five hundred eggs over a couple days, and then croak.

What a happy life.

One ounce of eggs will yield about thirty thousand silk worms. They will eat a ton - as in A TON - of mulberry leaves, and eventually yield about twelve pounds of silk. (Statistic from here.) I read somewhere, while researching this, that an entire shed of munching silk worms sounds like a heavy rain hitting a roof. If I wanted to do another rant on environment and the intelligent use of resources, this would be a fine time. It's as bad as chocolate. (No, I'm not giving up chocolate, EITHER.)

The silk worms that have not been allowed to hatch are dumped, in cocoon form, in hot water. (To get technical, any temp over about 180-190 F will destroy the luster of the silk.) Then the end of the cocoon filament is found, using a little thing much like a tooth brush, and it is spun straight from the pot of water to a silk reel. Four to eight cocoon filaments are reeled together, to form a thread (illustration of this, from ancient Chinese woodblock print, at left). There is still goo left on the filament (known as gum), and it helps the filaments stick together and stay strong enough for processing. In China, from there, the filaments are either twisted together to make something similar to yarn, or simply wound up as is, for use in weaving (that's known as thrown silk - don't know why). Once woven, the fabric is de-gummed, removing the last of the goo.

In Japan, the hatched cocoons are washed and stretched over a U-shaped form, and allowed to dry. This is where silk 'hankies' and 'caps' come from, used for spinning here in the west. But the Japanese have a different way of processing it into thread; low-tech, high quality, and moderately insane.





They do it entirely by hand. It is known as 'drawing' silk, and they simply twist it between their fingers, using a bit of spit to help it stick together (spit has enzymes that make the protein fibers sticky). From there it drops into a small bowl, and later, after the woman's hands have fallen off, someone winds it onto a bobbin. The only tools are the bowl and a post fastened to the floor to wrap the silk around.

Totally nuts.


This is one of the oldest and most spectacular of the silks found in China; it dates to the Warring States period, from about 500 to 200 BCE. Interestingly, it is dyed with cinnabar, aka mercury sulfide. (Remember in my Red post, where I wondered if people used cinnabar for dye? Apparently they do.) You can see by this fragment that even then silk production was quite complex, and it's easy to believe there was at least a couple hundred years for development before this piece was produced.

By 1000 CE, sericulture had traveled to Moorish Spain, and from there edged up into Europe. (The piece below is from Andalusia, around 1000 CE.)


Silk production has doubled in the last thirty years, even with all sorts of cheap synthetics hitting the market. Since the 1970s, China has, again, dominated the world production of silk.

As they should.

Who the hell comes up with this stuff?!

7 comments:

Donna Lee said...

I can't imagine pulling silk from cocoons by hand and not going blind/stark raving mad. And I'm in wonder at how you managed to put together an interesting post whilst in the middle of a season changing migraine. I am not on that many pain meds and my brain is not functioning well enough to type without lots of errors.

Alwen said...

Pliny sort of got it right, in a roundabout way. Fur off leaves.

Have you ever heard an oak woods full of gypsy moth caterpillars, originally imported as a silk-making experiment? Their falling frass sounds like rain.

Yeah. Creepy. Makes my arm hairs stand up just to remember it.

Amy Lane said...

You must (MUST--do not doubt me on this!) buy (it will be cheap) and read a short little fantasy book called 'Bridge of Birds' by Barry Hughart. He is a Chinese Historian, and you will get a crash course of sericulture in the first chapter (much like yours, only told in character)--and then watch it go hideously, gloriously wrong.

Your article was awesome!

Roxie said...

"Women of the silk" by Gail Tsukiyama is an engrossing novel about the silk processors' lives and how the invasion of China by Japan changed them irrevocably.

Love your essays. I would buy the collection in book form if you ever get around to it.

Anonymous said...

I bet Pliny needed thick geek glasses! But seriously,if you haven't been to wormspit.com you should go! Great pics of the whole process from silk worm lifecycle to cocoon to silk!Projects, links to get your own moths and food. He has a great website!

Angelnegra said...

I enjoyed reading your post very informative.

Anonymous said...

i liked reading the article... it is really informative.. actually i have a project to make on sericulture and i like the information so i am going to use the information. thank you!!!