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Welcome to the first post of The Spool, the Bolt Threads blog. The Spool is your front row seat on our journey from idea to commercial product. You’ll get insight into our goals, challenges, and what’s on our mind. Join us in unraveling the mystery of developing new materials and making a new technology a reality!
We’re replicating natural silk production, but this isn’t the first time there’s been a global hunt for the secrets of silk.
For millennia, people have been fascinated with the magic of fabric, especially silk. Sericulture, the practice of making silk and raising silkworms (and your vocab word for the day) began in China around 3000 BCE.
The chief wife of the first Emperor of China is credited with accidentally discovering how to reel silk when a silkworm cocoon dropped from a tree into her cup of hot tea. Sericulture was ancient China’s economic secret weapon: they were the only ones who knew how to fabricate the lustrous luxury that is silk and they reaped the rewards on the trade routes of the Silk Road. But secrets are hard to keep, and eventually the cat was out of the silken bag.
There are multiple stories about how sericulture made its way west, each tale of espionage more intriguing than the last. A Chinese princess is said to have smuggled out silkworm eggs in her hairpiece. Insect eggs in your hair. Talk about commitment to fashion.
Europe desperately wanted to end their reliance on China for silks, and one story credits two monks with sneaking back silkworm eggs in their bamboo walking sticks. We don’t know for sure, but we assume Emperor Justinian consequently did a victory dance.
Hundreds of years later, sericulture was still a closely guarded secret. In 1308 in the Italian city state of Lucca decreed that the punishment for engaging in the silk industry outside of the town precinct would be death. Silk was so powerful that betraying its secret was punishable by death.
Everyone wanted to keep the majesty of silk to themselves. When Queen Elizabeth I started wearing silk stockings, she insisted that her maids of honor wear stockings of a different fabric. She needed to eliminate all rivals of her comely ankles, and that meant forbidding silk.
Silk was (and is) prized for its visual appeal in fashion, but throughout history it’s served a variety of other applications including paper, canvas, bowstrings, parachutes, tires, and even gunpowder bags.
Most of this silk came from silkworms but some people also utilized spider silk. Early Romans and Greeks used spider silk to weave fabrics and nets and to bandage wounds. Australian aborigines used spider silk for fishing lines and nets and even rubbed crushed spiders on the nets to attract fish. Until World War II, the cross hairs on many weapons were made of spider silk.
Silk has always been mysterious and elusive. For millennia, the desire for the beauty and function of silk has tantalized people. Join us on the next chapter of the story, as we give you a glimpse in how we’re taking material production beyond spiders and silkworms. And unlike the Lucca silk weaving guild, you won’t be bound to secrecy.