Brent Seales/Lexington Herald-Leader/MCT via Getty
Lead often gets a bad press. But its discovery in ancient Graeco-Roman ink could make it easier to read an early form of publishing – precious scrolls buried by thein AD 79.
Some 800 scrolls, part of the classical world’s best-surviving library, have tantalised scholars since they were unearthed in a villa in the ancient Roman city of Herculaneum in 1752. About 200 are in such a delicate state that they have never been read.
Unrolling the charred scrolls can destroy them, so people have been X-raying the bundles in the hopes of discerning the writing inside. But progress has been slow – it is difficult to detect the difference between the letters and thethey are written on.
Now physicist Vito Mocella of the Italian National Research Council and his colleagues have revealed lead in the ink on two Herculaneum papyri fragments held in the Institute of France in Paris.
The presence of lead means that imaging techniques could be recalibrated to pick up the metal, something at which X-rays excel.
“This really opens up the possibility of being able to read these scrolls,” says Graham Davis, a reader in 3D X-ray imaging at Queen Mary University of London. “If this is typical of this scroll or other scrolls, than that is very good news.”
Trail of lead
This is not the first time someone has suggested that the Herculaneum papyri inks might contain lead. In 2009, computer scientist Brent Seales at the University of Kentucky in Lexington picked up on the presence of metal in the scroll ink.
Emmanuel Brun et al
Mocella’s team has now used a powerful particle accelerator known as a synchrotron to confirm that finding, challenging the long-standing wisdom that metal-based inks hadn’t been widespread until the 4th or 5th centuries AD. “From a historical point of view, it is a surprise,” says Mocella.
Mocella’s team suggests that the high concentration of lead makes it likely the metal was purposely introduced into the ink, rather than coming from water contamination or a metal inkpot. It could have served as a pigment or as a binding medium.
Whatever the lead’s use then, it seems to have a clear use now. “This is the way we will get back some of the lost knowledge of antiquity,” says Richard Janko, a classicist at the University of Michigan in Ann Arbor.
Mocella and his team will start X-raying scrolls from the National Library in Naples in July, with the scanners looking for lead.
Journal reference: PNAS, DOI: doi/10.1073/pnas.1519958113
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