Didcot (United Kingdom) (AFP)
Carbonized during the eruption of Vesuvius, Roman papyri have kept their secrets for nearly 2,000 years. Scientists are trying to decipher these "fragile as butterfly wings" documents using a particle accelerator.
Preserved at the Institut de France in Paris, these ancient papyri from the archaeological site of Hercunalum, near Naples, made the trip to the center of England to be unrolled virtually.
"The idea of a parchment is that you can simply unroll it and read it, but these papyrus can not be unwound because carbonization has made them extremely fragile," AFP told AFP. Professor Brent Seales, who has been working for some 20 years developing non-invasive techniques of deciphering.
Its tool: a synchrotron, a ring of 500 meters circumference where electrons turn at very high speed and emit a kind of very powerful X-ray that allows to cross the material. Called Diamond Light Source, it produces a light ten billion times brighter than the sun and functions like a giant microscope, whose data are then decrypted by computer using artificial intelligence.
- "Villa of papyrus" -
The scrolls were discovered between 1752 and 1754 during excavations at the Herculaneum site near Naples. Unlike Pompeii, ravaged by lava during the eruption of Vesuvius in 79 AD, Herculanum was struck by a fiery cloud, which covered the city with ashes.
Under this thick layer, the houses were intact. One of them, the "Villa of Papyrus", housed an important library of more than 1,800 scrolls of text, preserved by ashes but carbonized, impossible to unroll.
In 1802, six of these rolls were donated by the King of Naples to Napoleon Bonaparte, who entrusted them to the library of the Institut de France in Paris, with the mission of reading them. But the matter is ultra friable, and the first two tests, in 1817 then in 1877, fail.
The rolls are returned to Naples, where, in 1986, a method of chemical unwinding allows detaching one, in several hundred small fragments, "very difficult to read" because of the nature of the ink, says Yoann Brault , studies engineer at the Institute's library.
In the synchrotron, rays are sent on the samples and must allow to create a very high resolution image in three dimensions "without having to destroy, open or manipulate" the parchments, explained the professor, also director of the initiative digital restoration at the University of Kentucky.
"The reconstruction process, highly computerized, gives us the information of what was inside," he continued.
Transporting the samples from Paris to England presented "some risks", admitted Francoise Berard, director of the library of the Institute. "But we obviously wanted to help in the discovery of the content," she added, ensuring it took "maximum precautions" for these papyrus "fragile as butterfly wings".
- Epicurean texts -
Before Professor Seales, other scientists have already used non-invasive techniques to decipher these documents.
In 2014 in France, a CNRS researcher, Daniel Delattre, had already been able to unveil the content of these papyrus using a new technique to decipher the texts without unrolling them, phase contrast X-ray tomography .
We have thus been able to recognize some Greek letters, from the pen of an epicurean philosopher, Philodemus of Gadara.
"This confirmed that these scrolls contain mainly Greek writings, in one person (Pison, the father-in-law of Julius Caesar, Ed) interested in the epicurean philosophy", analyzes Michel Zink, perpetual secretary of the Academy of Inscriptions and Beautiful letters.
"Unlike the Stoic philosophy, whose texts, judged compatible with Christianity, were recopied in the Middle Ages, Epicureanism was not in the odor of sanctity, and his texts have rarely been preserved," said this medievalist.
"This is why these rolls are so important," concludes the historian, according to whom "we can hope to succeed in reading entire sentences, and perhaps one day, an entire text".
© 2019 AFP