Thursday, May 26, 2005

Stanford lab reveals hidden writing on ancient parchment / Scientists analyze Archimedes text at accelerator center

"A super-X-ray beam in Menlo Park is literally shedding new light on the achievements of an ancient titan of math and engineering who lived almost 23 centuries ago.

Associated Press photo, 1999, by Beth A. Keiser

Just as today's scientists learn the latest developments from journals such as Science and Nature, scholars circa A.D. 1000 consulted scientific writings etched in ink on goatskin parchments. A millennium later, time has seriously eroded these inky ruminations of scholars who perhaps scribbled within earshot of chanting monks, feudal lords, suffering serfs and armor- clanking knights.

Those old writings are being recovered thanks to scientists at Stanford Linear Accelerator Center. With excruciating slowness and care, they have begun using a beam of X-ray radiation no thicker than a human hair to scan a goatskin parchment known as the Archimedes Palimpsest. It's of unusual interest because it shows how advanced mathematics -- the so-called Queen of the Sciences -- was in ancient times, at least in the mind of a legendary mathematician.

Normally, the SLAC X-ray beam is used for more immediately practical purposes such as research in solid-state physics, materials science and structural biology.

In this case, though, the beam is revealing 'the previously hidden work of one of the founding fathers of all science,' said Keith Hodgson, director of the Stanford Synchrotron Radiation Laboratory, where the research was conducted this month. A color picture of a high-resolution image of the palimpsest, recovered via the Stanford technique, is reproduced in a short news item in Thursday's issue of the journal Nature.

Hardly any of the palimpsest's original ink is left -- only a layer between 1- and 2-millionths of an inch thick. The SLAC technique is roughly akin to peeling off wallpaper and discovering older, badly faded wallpaperings beneath it.

The palimpsest is the only known source of information on two previously unknown treatises of Archimedes, who lived in Sicily three centuries before Jesus. In a sense, Archimedes -- an ingenious mathematician and inventor -- was both the Einstein and Edison of his epoch.

In about A.D. 1000 in Constantinople, the 174-page palimpsest was copied from papyrus versions made over the centuries from even earlier replicas of Archimedes' original calculations and mathematical diagrams. The palimpsest includes his discussions of geometrical topics such as circles, spheres and cylinders, as well as his insights into the mathematics of infinity.

The manuscript suffered various abuses -- including the scraping or washing off of most of the original text, which was then written over with prayers -- sometime in the centuries between about A.D. 1000 and 1906. In the latter year, a philologist examined the palimpsest in an Istanbul church and identified its underlying text as Archimedean.

Soon after, the palimpsest was lost. Apparently unaware of its identity and value, an unknown forger painted gold-leaf medieval-style pictures in the book. About 1930, a Parisian collector purchased the palimpsest and kept it at home for several decades. In 1991, an antiquities expert at Christie's auction house in Paris saw the palimpsest and recognized its identity. In 1998, it was sold to an anonymous buyer for $2 million.

Most of what we know about ancient thought is indebted to those innumerable medieval scribes, like the one who produced the Archimedes Palimpsest. They copied and commented upon ancient writings, to preserve the intellectual treasures of antiquity in the days before Gutenberg-style printing, Xerox machines and PDF files sent via the Internet.

"If you see the palimpsest, you have goose bumps," said Uwe Bergmann, a scientist who is spearheading the SLAC investigation. Today's scientists are "in effect Archimedes' great-great-great-grandchildren."

Legends (some of them dubious) surround Archimedes' life: For example, that he discovered a key principle of hydrostatics when he sat in a tub and noticed the water rising around him as it was displaced by his body. Thrilled, he supposedly yelled, "Eureka!" and excitedly ran naked through the streets. He also allegedly built a giant mirror that reflected and focused the sun's rays into an ancient version of a "Star Wars" laser; according to myth, he used the device to burn the sails of invading Roman ships.

Another story holds that he was killed by a Roman soldier about 212 B.C., when Romans invaded Syracuse. Legend says that the soldier killed Archimedes because he was too busy doing calculations to obey the soldier's order.

So far, the SLAC analysis hasn't altered scholars' previous understanding of Archimedes' accomplishments, said Reviel Netz, a Stanford classics professor who is involved with the project.

But, Netz added, new understandings about Archimedes and other ancient geniuses might arrive in the future, thanks to such high-tech methods.

"Greek civilization has produced lots of writings, and many of them (were illegible to past scholars) because the techniques available for reading them were not up to the job," Netz said.

The SLAC X-ray beam is a type of radiation known as synchrotron light. It's generated when electrons traveling at almost the speed of light race around a curved "storage ring," emitting radiation ranging from X-ray to infrared wavelengths in the process.

The SLAC ring is surrounded by different experiments, like piglets suckling at different nipples on a sow. For example, a common alternate experiment uses synchrotron radiation to image exquisitely precise atom-by- atom images of organic molecules.

"It's far too early" to know how the SLAC technique might eventually modify our understanding of Archimedes, Netz said. Still, "we can see very well that the technique is very powerful. We're refining techniques, which no doubt will be very valuable for the study of (aged) manuscripts in general."

The person who bought the palimpsest in 1998 has since lent it to Walters Art Museum in Baltimore for research purposes. Walters, in turn, has provided it to various scientists, at SLAC and elsewhere, for recent analyses. Other institutions involved in the palimpsest's research include RB Toth Associates, Rochester Institute of Technology, Johns Hopkins University, ConocoPhillips and Rutgers University.

Sometimes, such scientific analyses of medieval writings require judgment calls. For example, a scholar might have to decide: Was an inky marking intentionally inscribed by the author? Or is it just a stray fleck of ink that was dislodged over the centuries?

"None of these (scientific) techniques are magic wands that transform an illegible text into a text one can read," Netz said.

Being so precious, the palimpsest is handled with extreme care. It was brought from the Baltimore Museum to Menlo Park by a museum official who carried it with her as carry-on luggage in the first-class section of an airplane.

To ensure SLAC's X-ray beam wouldn't damage the palimpsest, Bergmann and his colleagues exposed another old goatskin parchment to the beam, then sent it to a researcher in Ottawa for analysis.

The researcher, Gregory Young of the Canadian Conservation Institute, analyzed fibers in the test parchment. He concluded, he told The Chronicle, there was "no negative effect of the synchrotron's high-flux X-rays on the molecular stability and integrity of the test parchment ... (Thus) the exposure will have no deleterious effect on the parchment of the Archimedes Palimpsest."

In theory, humidity extremes (too dry or too damp) can damage the palimpsest. Hence, while X-raying the palimpsest at SLAC, the Stanford team made sure the room humidity stayed around 50 percent, partly by "buying a $100 Sears humidifier," said Bergmann, a physicist and X-ray spectroscopist who received his doctorate in physics at State University of New York at Stony Brook.

They even devised a procedure to protect the palimpsest in case power failure shut off the humidifier -- the precious parchment would be slipped into a hermetically sealed, low-humidity container.

Archimedes dabbled with one form of calculus -- the mathematical basis of much modern science -- two millennia before 17th century physicist Isaac Newton figured out how to use it to calculate planetary orbits.

The ancient mathematician was so brilliant, Bergmann said with a laugh, that "I'm sure if he were sitting here watching me (analyzing the palimpsest), he could think of a way we could do the experiment better -- he might say, 'Why don't you turn the detector this way?' "

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