The last unreadable pages of the works of ancient mathematician Archimedes are being deciphered after more than 1000 years in obscurity, thanks to an x-ray imaging technique being used at the Stanford Linear Accelerator Center (SLAC). The research will offer the most complete record of Archimedes' works since the middle ages. A team of scientists is using x-ray fluorescence (XRF) imaging to finally unlock these scientific secrets, hidden from view since antiquity on a goatskin parchment manuscript. The manuscript uniquely records several of the works of the legendary third-century B.C. mathematician, who discovered the principles of density and buoyancy ("Archimedes' principle") while taking a bath. Archimedes' work is considered to be the foundation of modern mathematics. A page from the Archimedes Palimpsest painted over with a forged religious image (left), and SSRL's x-ray view of the same page showing text hidden behind the paint. The text of the Archimedes Palimpsest, a manuscript of unique importance to the history of science, presented a monumental challenge for imagers to reveal and scholars to decode. In the 10th century, an anonymous scribe copied Archimedes' treatises in the original Greek onto the parchment. But three centuries later, a monk "palimpsested" the parchment: He scraped away the Archimedes text, cut the pages in half, turned them sideways and copied Greek Orthodox prayers onto the recycled pages. Adding further injury, forgers in the early 20th century painted religious imagery on several pages in an attempt to elevate the manuscript’s value. The result was the near obliteration of Archimedes' work, except for the faintest traces of ink still embedded in the parchment. In 1998, this unique manuscript was purchased by an anonymous collector at an international auction, who then entrusted it to the care of The Walters Art Museum in Baltimore, Md., for conservation and study. Using modern imaging techniques that rely on visible and ultraviolet light, the faint traces of remaining original ink yielded up most of the hidden text and brought to light stunning discoveries about Archimedes. But certain pages resisted even the most intensive attempts at deciphering. Paint and stains completely obscured a few remaining parts of the original text, making it impossible to read using multispectral imaging. It was here that the intense x-ray beam produced at SSRL proved invaluable. The x-rays pass right through the grime and paint, like a child's magic pen that reveals invisible ink. "We're getting a vastly better understanding of one of the greatest minds of all times," said SSRL scientist Uwe Bergmann. "We are also showing it is possible to read completely hidden texts in ancient documents without harming them." In March of this year, experiments at SSRL revealed a previously indecipherable page of one of Archimedes' treatises, "On Floating Bodies." The same experiments also brought to light the identity of the priest who erased the Archimedes texts. His name was Johannes Myronas, and he finished transcribing the prayers on April 14, 1229, in Jerusalem. "We have already discovered an astonishing amount of new information using x-ray fluorescence and eagerly hope for more," said William Noel of The Walters Art Museum and director of the Archimedes Palimpsest collaboration. A team of academics -- x-ray scientists, rare document conservators and scholars of ancient mathematics -- has returned to the experimental station at SLAC to scrutinize more of the ancient Greek characters, unseen for centuries, scrolling across computer screens as the x-ray beam carefully scans the parchment. The team is paying special attention to seeing through the forged gold paintings that coat several pages, including previously unread sections of Archimedes' greatest treatise, The Method. For more information, visit: www.slac.stanford.edu