In 79 A.D, Mount Vesuvius erupted and buried the ancient Roman town of Herculaneum under 60 feet of rock and ash. It wasn’t until the 18th century that archeologists uncovered the remains and began to unearth the lives that had been buried on that horrific day so long ago.
One of the most intriguing finds at the Herculaneum site was a small, ham-shaped item made of silver-plated bronze. Uncovered during the excavation of a grand Roman villa and small enough to fit within a coffee cup, the artifact was as small as it was curious. After careful cleaning and examination, experts concluded that the item was an ancient portable sundial made in the shape of Italian prosciutto.
The ‘pork clock’ was essentially the pocket-watch of its day. Excavated in the 1760s from the remains of the Villa of the Papyri, the unusual timepiece is a rare find. According to Alexander Jones, a historian at New York University, fixed sundials were commonplace across the ancient world, but we’ve only discovered 25 ancient portable sundials.
These portable watches hung on a string, and users would tell the time by checking where a shadow fell across an irregular grid etched into the face. By aligning the sun’s shadow with the grid-line for the current month and then marking the location where that shadow intersected with the hour, users would have an accurate reading of the time.
In an effort to truly understand the interesting artifact, Christopher Parslow, Professor of Classical Studies at Wesleyan University, decided to recreate the ancient timepiece with modern technology. In consultation with Christopher Chenier, a visiting professor of arts, he produced a modern replica of the relic using a 3-D printer.
Because the original clock was missing the piece that would have cast the shadow, the gnomon, Parslow had to recreate it by referencing notes from 18th-century museum curators who were able to examine the item when it was still intact. According to the notes, the original gnomon was in the shape of a pig’s tail. So, he recreated the pig’s tail and added it to his 3-D design.
Bill Herbst, Professor of Astronomy, was brought on board next. His job was to help work out how the device would have functioned and just how accurate it would have been at getting ancient Romans to their meetings on time. Herbst was intrigued by the pork clock and decided to present it to his students as an object of study.
His students determined that the portable sundial was accurate within a 10-minute window. However, Herbst also notes that the ancient Romans had a very different view on keeping time than the modern world. Modern timekeeping is stable. An hour will always contain 60 minutes, but this was not the case for the Romans in Herculaneum. Ancient Romans divided the time from sunrise to sunset into 12 equal parts. As the seasons changed and days grew longer or shorter, so did the lengths of the blocks of time between sunrise and sunset. For the Romans, an hour in June would have been much longer than an hour in December.
In presenting the results of his experiments, Parslow notes that using the timepiece requires finesse. However, the ancient Romans didn’t need to know the time down to the minute and having a portable sundial might have served more as a status symbol for the owner. Parslow does admit to not having an answer to one lingering question. Why did the original maker choose the shape of a leg of ham? It seems like an odd choice, but Parlow does have a theory. The pig is a prominent symbol in Epicurean philosophy, a school of thought that focuses on pleasure and living life to the fullest. Archeologists uncovered texts related to Epicureanism at the villa along with the sundial. Curator of antiquities at the J. Paul Getty Museum, Kenneth Lapatin, believes the shape may have been nothing more than a macabre joke, encouraging the wearer to enjoy their lives to the fullest before ending up like the ham.
