In 1907, Johan Ludvig Heiberg came upon a many centuries-old book in a Constantinople library that contained Greek Orthodox prayers and rites. The book was significant in itself, but on closer inspection using a magnifying glass, Heiberg realized an even greater treasure was hidden below the surface text. What he had discovered were seven treatises by Archimedes in the original Greek, among which is the only known copy of the illustrious mathematician's "Method of Mechanical Theorems."

The treatises were copied in the 10th century and are the earliest surviving works by Archimedes, who lived in the third century B.C. The writing was washed and scraped off 200 years later by a scribe who reused the pages for a prayer book, creating a twice-used parchment book known as a palimpsest. The later script, also in Greek, ran at a 90-degree angle to the original text, which in places is still discernible to the naked eye.

In this hyperspectral image of the palimpsest, heightened contrast allows researchers to see Archimedes' words, which are running perpendicular to the lighter, more recent writing.

Heiberg was able to translate some of the 174-page book but was limited by the science of the time.

Today, equipped with much more than a magnifying glass, two teams of scientists, from Johns Hopkins and the Rochester Institute of Technology, are taking cracks at revealing the hidden text to allow scholars to complete the translation. The two groups, winnowed from a field of five, are in competition to determine whose methodology will prove to be most effective. A decision on who will analyze the whole of the manuscript is expected to be made by the end of the year.

William Christens-Barry, a research faculty member at the School of Medicine, and Johanna Bernstein, a lecturer in the Whiting School's Department of Materials Science and Engineering, are leading the Hopkins team, which is operating under the auspices of the School of Engineering.

William Christens-Barry, seated, heads up the Hopkins team that has been working with the Walters Art Museum to recover the writings of Archimedes. With him in the musuem's Eureka! Room are, from the left: Natalie Tchemetska, an ancient Greek scholar from the University of Cambridge; William Noel, associate curator of manuscripts and rare books at the Walters; and Abigail B. Quandt, the museum's senior conservator of manuscripts and rare books.

By using the latest in imaging techniques, assisted by the Columbia-based imaging company Microcosm Inc., the Hopkins scientists were able to complete the first phase of the imaging work earlier this month, deciphering five of the manuscript's pages.

Christens-Barry said the challenge in this endeavor is working with a text that is in a very deteriorated condition. Over the years the book has been moved at least five times, deliberately defaced, damaged in a fire, threatened by an earthquake and battered in political upheavals.

Its whereabouts unknown since 1920, the Archimedes palimpsest resurfaced in New York at a 1998 Christie's auction, badly defaced by mildew and scorched around the edges. Purchased for $2 million, the anonymous owner entrusted the book to the Walters Art Gallery, recently renamed the Walters Art Museum, where it is now being conserved and studied.

Christens-Barry said what he is looking for are the faint residues of the original 10th-century ink, or products of chemical reactions between the ink and the parchment.

"The manuscript is written on very old parchment, which is made from sheepskin. And like any very old skin, this parchment has been ravaged by age and a difficult life. It is warped and wrinkled, cracked, stained; it's been damaged by fire, mold and insect holes and had been repeatedly tatooed with text," said Christens-Barry, a former principal staff member at the Applied Physics Laboratory.

The first technique Christens-Barry employed was multispectral imaging, which examines the spectral detail of two-dimensional images, a technique commonly used in remote sensing such as satellite images of the Earth's surface. Next he used confocal microscopy, an optical technology used to determine the structure of human cells. The aim of the process is to use a two-dimensional image to assemble a three-dimensional stack of images, or what Christens-Barry calls "a volumetric picture of an object." The data, once acquired, is then stored on a computer, where the researcher can "slice off" and examine each layer of text.

"It was quite obvious that this palimpsest has its own life story, a history," Christens-Barry said. "It is almost like an archaeological record where the deposition of strata records the history over time."

The third technique used, called hyperspectral imaging, recovers images of the text by bombarding it with ultraviolet light. This light causes the substrate to fluoresce, or glow, in spots where the erased 10th-century ink had altered its chemistry. The noninvasive procedure produces a heightened contrast of each stain, ink residue and discoloration upon the page.

"We are rendering the writing more visible; that is the goal--and part of that will be to try and eliminate any distracting or interfering other content, like the writing that lies over it," he said. "In some places we will succeed greatly. In other places it will always be very hard to see; that is just the nature of the problem."

Image enhancement of ancient text has been an "outside interest" of his for some time, said Christens-Barry, whose field is prostate cancer research. In the past he has informally advised several museums on the digital imaging of Egyptian papyri. So the opportunity to work with such a historically important text as the Archimedes palimpsest, he said, is the chance of a lifetime.

He first learned of the palimpsest when he saw it on display at the Walters and only later became aware of the owner's challenge to identify the most successful recovery technique.

"It has been a tremendous opportunity for me to work with a manuscript of such scientific importance and that has such a fascinating history," he said. "We are not just filling in and straightening out a historical record; it is an attempt to bring to life the unique insight of Archimedes, an insight that can advance how scientists approach their work even today."

The book also contains the only known copy in Greek of another Archimedes thesis, "On Floating Bodies," according to William Noel, associate curator of manuscripts and rare books at the Walters.

Noel has likened the seven treatises, including several diagrams, to a look inside the contents of Archimedes' brain.

Archimedes was born around 287 B.C., in Syracuse, Sicily, and died in 212 or 211 B.C. This inventor, physicist and engineer was a major thinker of his time. He created what is known today as the Archimedes screw, a corkscrewlike scoop commonly used for irrigation purposes. He also is frequently associated with the term "Eureka!" The story goes that Archimedes was in his tub one day when he noticed the displacement of water caused by his own submersed mass, prompting him to jump up and run naked through town shouting the phrase, Greek for "I have found it."

"It is a great privilege to have this document at the Walters," Noel said. "And to have worked on this project thus far with The Johns Hopkins University has also been a very valuable learning experience. To have someone of Bill's experience and caliber is just extraordinary. And while it is pure coincidence he is just up the road, it is fabulous that Johns Hopkins has the skills in this area that we have required."

Noel said that once the winning team is selected, it will likely take four to five years to finish translating the book. The owner is funding the work.