When Mount Vesuvius, a stratovolcano in Italy, erupted in A.D. 79, it wiped out the city of Pompeii and the town of Herculaneum, killing thousands and burying fine villas in lava and ash. One of these villas, however, turned out to be a treasure trove of scrolls.
In the 1750s, a library with over 2,000 ancient papyrus scrolls that had been burned by the volcanic heat was discovered in what is known as the Villa of the Papyri, which is believed to have once belonged to a Roman statesman.
Since the discovery of the Vesuvius scrolls, there have been many attempts to read them, ranging from pouring mercury on them to soaking them in rosewater, said American Society of Papyrologists president Jennifer Sheridan Moss.
Although some of the scrolls were unrolled and deciphered, some of the methods that were employed to unroll the scrolls damaged the fragile documents, prompting historians to lock the remaining and still rolled up scrolls in the National Library of Naples in Italy.
Researchers, however, have tried to read the ancients documents sans unrolling them using X-ray tomography, a process which involves taking x-rays from a number of angles in order to recreate a three-dimensional image of the object.
The process, however, did not work so researchers resorted to another similar technique known as X-ray phase-contrast tomography (XPCT). Compared with regular X-rays, the XPCT can distinguish the charcoal ink used in the ancient scrolls from the burned papyrus' surface.
XPCT involves tracking the changes in the speed, or phase, of an X-ray beam while it passes through the material. With the measured phase difference, researchers were able to reproduce what the letters looked inside the rolled scrolls.
"We show that X-ray phase-contrast tomography can reveal various letters hidden inside the precious papyri without unrolling them," the researchers reported in the journal Nature Communications on Jan. 20.
The researchers said that the method may possibly pave the way for the reading of the scrolls more fully and can be improved as the experiment was a proof of concept. They have so far analyzed six scrolls that were once given to Napoleon Bonaparte and were able to decipher some of the letters that were written inside these still rolled up and charred scrolls.
"This pioneering research opens up new prospects not only for the many papyri still unopened, but also for others that have not yet been discovered," the researchers wrote.