BALTIMORE (AP) _ A particle accelerator is being used to reveal the long-lost writings of the Greek mathematician Archimedes, work hidden for centuries after a Christian monk wrote over it in the Middle Ages.
Highly focused X-rays produced at the Stanford Linear Accelerator Center were used last week to begin deciphering the parts of the 174-page text that have not yet been revealed. The X-rays cause iron in the hidden ink to glow.
"One of the delightful things is we don't know what it's going to say,'' said William Noel, head of the Archimedes Palimpsest project at the Walters Art Gallery.
Scholars believe the treatise was copied by a scribe in the 10th century from Archimedes' original Greek scrolls, written in the third century B.C.
It was erased about 200 years later by a monk who reused the parchment for a prayer book, creating a twice-used parchment book known as a "palimpsest.'' In the 12th century, parchment _ scraped and dried animal skins _ was rare and costly, and Archimedes' works were in less demand.
The palimpsest was bought at auction for $2 million in 1998 by an anonymous private collector who loaned it to the Baltimore museum and funded studies to reveal the text. About 80 percent of the text has been uncovered so far.
"It's the only one that contains diagrams that may bear any resemblance to the diagrams Archimedes himself drew in the sand in Syracuse 2000 years ago,'' Noel said.
While reading an article on the text, Stanford physicist Uwe Bergmann realized he could use a particle accelerator to detect small amounts of iron in the ink. The electrons speeding along the circular accelerator emit X-rays that can be used to cause the iron to fluoresce, or glow.
"Anything which contains iron will be shown, and anything that doesn't contain iron will not be shown,'' Bergmann said.
Bergmann normally uses the accelerator, in which electrons are pushed to near the speed of light, to study the structure of water and how water is split to create oxygen during photosynthesis.
Most of the text has been revealed by scientists at Johns Hopkins University and the Rochester Institute of Technology who used digital cameras and processing techniques as well as ultraviolet and infrared filters developed for medicine and space research.
The so-called Archimedes Palimpsest includes the only copy of the treatise "Method of Mechanical Theorems,'' in which Archimedes explains how he used mechanical means to develop his mathematical theorems. It is also the only source in the original Greek for the treatise "On Floating Bodies,'' in which Archimedes deals with the physics of flotation and gravity.
Three of the undeciphered pages were imaged last week, and the rest are expected to take three to four years to complete, Noel said.
