hide captionUsing a specialized X-ray technique, scientists and scholars at the Walters have been able to look through forged paintings on the parchments to see the Greek characters beneath.
Courtesy of the owner of the Archimedes Palimpsest
Using a specialized X-ray technique, scientists and scholars at the Walters have been able to look through forged paintings on the parchments to see the Greek characters beneath.
Courtesy of the owner of the Archimedes Palimpsest
hide captionMold, bookworms, and general decay have left the ancient parchment in poor shape.
Archimedes Palimpsest Project
Why would anyone pay $2 million for a tattered book of Christian prayers from 1200 A.D.? The anonymous philanthropist who coughed up the sum in 1998 wasn't lured by the holy writings. He was after the faint ink beneath — mathematical theorems and diagrams from the Greek scholar Archimedes, who lived more than 2,000 years ago. It's the oldest known copy of his work, but the writings were barely legible. But now, a new restoration technique may make it possible to recover all of Archimedes' original text.
As the legend goes, Archimedes discovered the principle of buoyancy in his bathtub, prompting him to shout "Eureka!" Regardless of whether this story is true, Archimedes was, without a doubt, a great mathematician. Little of his work has made it down through the ages, but what has survived is startling. He writes about infinity — different levels of infinity, actually — which is astounding for a scholar from the second century B.C.
The prayer book is known as the "Archimedes Palimpsest" — a palimpsest is a document with hidden writing — and it resides at the Walters Art Museum in Baltimore.
"It’s the ugliest thing in the collection," says William Noel, curator of rare books at the Walters. "It is also by far the most important text manuscript in a palimpsest that the world knows."
Noel cannot reveal the owner's name; he'll say only that he has a big heart. And a big agenda. He wants every possible word of Archimedes extracted, even though some pages are at the point of crumbling into dust, and others have fallen victim to the ravages of bookworms.
A parchment shortage is to blame for the overwriting. The original text apparently sat in a library in Constantinople until 1229 A.D. Then a scribe erased it; he needed someplace to write a prayer book. Seven hundred years later, Archimedes expert John Ludwig Heiberg discovered the traces of Archimedes after reading a few lines transcribed by a scholar in 1899. Over the next few decades, the book had a mysterious life, disappearing and reappearing. Eventually, it was sold at auction.
Since then, scholars and scientists have used ultraviolet light to make letters stand out. But the method did not work on every page. Some were too damaged; others were covered with forgeries – paintings created in the 20th century and made to look older to drive up the value of the book.
Of Spinach and X-Rays
Popeye's favorite vegetable holds the key to uncovering the rest. Uwe Bergmann, a Stanford physicist, was attending a conference in Germany when he stumbled upon an article describing the Archimedes Palimpsest. At the Synchrotron Radiation Laboratory, a Department of Energy research facility in Stanford, Bergmann studies the physics of photosynthesis — in particular, photosynthesis in spinach.
"I read that there is still some significant text missing, and that there are forgeries and that there's iron in the ink. When I read the word 'iron,' I said, 'Wait a minute, we are studying iron in spinach.' I thought we should be able to use the same method and just then do imaging with it."
Bergmann proposed his idea in an e-mail to William Noel, suggesting that the Stanford Linear Accelerator in California might be used to provide the necessary X-ray pulses through the document. Although at first concerned about potential harm to the document, Noel and the team conducted tests and decided the technique could be done safely. Bergmann’s idea worked. The first pictures emerged, line by line.
"I wished I could read ancient Greek. Very beautiful looking characters all over the place," Bergmann remembers.
The Man Who Erased History
The museum pressed ahead in its research and, just a few months ago, uncovered new diagrams and text in the original Greek — as well as the signature of the scribe who erased the Archimedes text and wrote the prayers on top.
"It just popped up," says Noel. "A guy called Johannes Myronas."
Despite the damage done to the ancient text, Noel doesn’t blame Myronas for the present state of the book. In fact, Myronas was most likely responsible for the book's survival.
"What a gift he gave us," Noel points out. "The great advantage of having them wrapped up in a Christian prayer book is that they were treasured and looked after for centuries."
So it was a love of math that preserved Archimedes' work for the first thousand years — and a love of God that carried it to the present.
Uncovering the Text: Lights, Camera, Reaction!
It's all just Greek to us, but to the owner of the Palimpsest and the research team at the Walters, the final images of the hidden text represent years of experimentation. To avoid damaging the ancient document, the team has had to be extremely selective in what techniques they employ to see the original writing. Here are the steps they took to create the images:
Step 1: Multispectral imaging.. Numerous digital photographs are taken using different wavelengths of light — the visible spectrum (white light) and ultraviolet. The resulting images are "stacked," and a computer algorithm filters the information to create an image of Archimedes' text. The technique worked, although the images were not of high enough quality to allow scholars and translators to decipher the characters.
Step 2: Multispectral imaging. The research team then tried combining two different wavelengths of light. The original text appears faint when exposed to visible light, but when viewed through only the red channel, it almost completely disappears. When viewing the image through the blue channel of ultraviolet light, the text appears backlit. Researchers took pictures under both wavelengths and combined them into a single image. The parchment appears white, the prayer book appears black, and the original text appears red.
Step 3: X-ray fluorescence imaging.. The initial results were excellent, but small portions of text still could not be deciphered. In this experimental X-ray imaging method, researchers use a particle accelerator to aim an X-ray pulse at a single page. The X-rays pass through the forged painting and hit atoms in Archimedes' ink. The X-rays remove the innermost electron, creating a kind of gap. A nearby electron fills the gap, and as it does, releases an X-ray. Sensitive detectors map the X-rays and create an image that shows the iron in the ink, highlighting the original Greek characters. Eureka!
The research team at the Walters has posted a detailed explanation of their research on their Web site.