استماع TOEFL C1: Archimedes Palimpsest

So we've been talking about different techniques of preserving artifacts.

Now I'd like to talk about an interesting case study

on the preservation of an artifact called the Palimpsest of Archimedes.

I'm sure you've heard of Archimedes,

one of the leading scientists in classical antiquity.

He lived more than 2,000 years ago in Greece.

He was regarded as one of the greatest mathematicians of history.

He figured out how to mathematically calculate the surface area and volume of a sphere,

and an accurate approximation of pi.

Unfortunately, not much of his work survived the passage of time.

He originally printed his findings on papyrus,

which was a processed and woven river reed fiber.

This material greatly decayed over time,

and his original scrolls were mostly lost.

What had survived had been brilliant.

Then, in 1906, a Palimpsest of Archimedes' writing was discovered.

Excuse me! Professor!

What is a Palimpsest?

Well, Parchment is made of animal skins that had been stretched tightly and dried.

Scholars used to take parchment that already had writing,

then wash it off with milk and write over the now-clean surface.

You have to understand that back then paper was uncommon for writing.

Instead, parchment was used for all the writing.

Okay!

Now, the interesting thing is that,

after the ink had been sitting on parchment for a long enough time, it soaks in.

And as the parchment aged, it dehydrated, making it lose much of its flexibility.

However, that extra drying time also made any captured inks within the skin rise to the surface.

So, seven hundred years later,

someone washed away a log of Archimedes' greatest work,

the letters and diagrams reappeared under the new letters.

It is now known as "The Archimedes Palimpsest",

and is probably by far the most important palimpsest anyone has found.

It contains the only known existing copy of Archimedes' finest work.

In it, he shows how mathematics can be applied to physical reasoning.

In 1906, the palimpsest was put on auction,

selling for 2 million dollars.

Luckily, it was not tucked away in a private collection.

The buyer agreed to have experts restore every single word Archimedes had written.

Now, his words can be shared with the world.

Unfortunately, we still have some problems with this Palimpsest.

Can anyone guess what they are?

Yes. Susan!

Well, it's been in storage for a long time,

probably not getting the proper care.

It's probably super crumbly, or moldy.

Exactly.

Some of it's moldy, some of it's been attacked by bugs.

The poor thing really went through the ringer.

On top of that, there is another problem with this Palimpsest.

Yes! John?

The letters on it aren't readable?

Essentially, yes.

Many archaeologists have used a variety of techniques such as Ultraviolet light

to try to make the letters more legible, but that didn't always work.

Fortunately, a physicist stepped forward - Bergman.

This guy was doing research on the iron within spinach leaves.

He proposed an idea that was very similar to how he was looking at iron in spinach.

He realized that the iron in the ancient ink would display

if exposed to a certain X-ray imaging method,

except for small portions of the text that couldn't be deciphered.

Now, with this technique, much of Archimedes' texts and drawings were revealed.