Hidden Library: How Science Is Virtually Unwrapping the Charred Scrolls of Herculaneum

University of Kentucky/Brent Seales
University of Kentucky/Brent Seales

Brent Seales called them Fat Bastard and Banana Boy. They were two charred, highly fragile relics that had survived the Mount Vesuvius volcanic eruption of 79 CE, which doused residents of Pompeii and neighboring Herculaneum in a searing blast of destructive gas and volcanic matter. Herculaneum was buried under 80 feet of ash that eventually became solid rock.

Entombed for centuries, the city was rediscovered in the mid-1700s. Incredibly, the library of Herculaneum (known as the Villa dei Papiri) was still filled with over 1800 scrolls, solidified into dark husks. The words inside—religious text, scientific observation, poetry—could provide unprecedented insight into human history. Yet unraveling them has proved difficult. The papyri are so damaged and rigid from lack of moisture that they suffer from a kind of archaeological rigor mortis. And unlike the paralysis that seizes the body upon death, this condition is permanent. Delicate attempts to open the scrolls by hand have been destructive. For a long time, it seemed as if the secrets of the texts would remain locked away for good.

But as Seales stared at the two hardened masses in front of him in 2009, he didn’t share that pessimism. A professor of computer science at the University of Kentucky, he believed that the manual unwrapping that had long failed could be replaced by virtual unwrapping—the digital opening of the texts using computer tomography (CT) scanning and software to penetrate inside the rolled-up scrolls, revealing layers once thought invisible to the eye.

“It’s the only library from antiquity that we have,” Seales tells Mental Floss. “All the knowledge that seems lost, your imagination can run wild.”


Seales first grew curious about the role of digital manipulation in 1995, when he was invited to assist the British Library in London in scanning and preserving Beowulf. Its 1000-year-old pages had been damaged by fire and warped by the passage of time, imperfections that 2D scans left intact. The use of special software and a 3D visualization, Seales realized, could make it possible to actually flatten the pages and restore smeared copy.

The idea of capturing and manipulating visual data came from Seales's experience in medical imaging, where CT scans can peer inside the body in a noninvasive manner. What if, Seales wondered, the same principle could be applied to the study of fragile documents? What if a relic could be examined in the way a radiologist can visualize, say, the lungs? "That was the eureka moment," he says.

A digital CT scan of a damaged scroll that is being reconstructed
A CT scan of a damaged scroll, with layers visible (L). The red outline is digitally reconstructed in a process called "segmentation" (R).

Seales believed he could use these diagnostic tools to virtually rebuild manuscripts, and returned to the British Library in 2000 to examine other warped documents. After taking images using a prototype of a machine that achieved 3D scans without physical contact, he wrote software that smoothed out the buckled and bunched pages. He likens it to a computer mimicking the tug of gravity, or reversing the direction of a billowing flag. The technique worked—he was able to achieve realistic, flat versions of centuries-old damaged pages.

But Seales believed he could set his ambitions higher: to not only virtually repair a damaged page, but peer inside the Herculaneum scrolls without the risk of causing additional harm. Like many scholars before him, the allure of Herculaneum's vast repository of knowledge had captured his curiosity.

However, the idea of subjecting the scrolls to even minimal handling was something few would consider. Only the Institut de France—one of four major holders of the scrolls—would entertain the idea, and it took four long years to convince them of the possibilities. In 2009, they finally granted permission to Seales's team to scan two Herculaneum scrolls they had in their possession. Officially, the scrolls were categorized as P.Herc.Paris 3 and P.Herc.Paris 4. Seales nicknamed them Fat Bastard and Banana Boy.

The easiest way to imagine the first part of his process is to visualize a sheet of dough that is covered with small red letters and then rolled up. Seen from its edges, the wrap displays its layers and colored pieces, though no observer could possibly identify sentences from that perspective. By slicing the roll into cross-sections as small as 14 microns thick (human hairs are around 75 microns) in a process known as volumetric scanning, Seales can then use geometric "mesh" to reassemble them into a readable surface, depicting the paper so it appears to be as flat as the day it was first written on.

In 2009, the technique allowed Seales to peer inside a closed Herculaneum scroll for the first time, revealing a fibrous labyrinth of data that initially looked like coiled string.

“We saw this amazing structure,” Seales says. But that's where things went wrong.

Seales had believed that trace metals commonly found in the ink of the period could be isolated by the imaging, separating them from the page once the scroll was unraveled and rendering the script legible. But so little of the metals were present that it didn't allow him to identify letters. Nor could Seales distinguish the carbon in the papyrus from the carbon in the ink, which rendered them indistinguishable from one another. The software also wasn't prepared to process the terabytes of data from the scan. While he technically had been able to look inside the scrolls, there was no functional way to determine what he was seeing.

Over the next several years, “Seales Stymied” became something of a headline in academic circles. That ignored the larger point: Seales had proven it was possible to retrieve images from inside the Herculaneum scrolls. It was now a matter of how best to visualize and process it.


The Herculaneum scans pushed Seales and his team to renovate their software, an act made easier by Seales’s sabbatical work as a visiting scientist at Google’s Cultural Institute in 2012 and 2013. “The interns helped me with the algorithms,” he says, which was a major perk of working for one of the world’s most concentrated and talented assembly of programmers.

His software was vastly improved by the time Seales was approached in 2014 by Pnina Shor, the curator of the Dead Sea Scrolls Project at the Israel Antiquities Authority. Shor had heard of Seales’s work and wanted to know if he could take a look at some CT scan data she had gathered from a 3-inch stick of parchment found in En-Gedi, Israel, in 1970. There was probably ink, but it was obscured by the folds and twists of the parchment.

A CT scan of the En-Gedi scroll, along with a virtual example of how it might look unfolded
The En-Gedi scroll's layers are tightly wound (L). Special software is able to isolate one layer to look for text (R).

Seales looked at the scans and applied his process for virtual unwrapping. He used a step he called "texturing," which identifies density differences and other data on the paper that indicate where ink has been applied and assigns a value to that point. Logging the information on individual voxels—the 3D equivalent of pixels—he's able to reassemble them so they appear as a familiar letter shape. The data is then flattened so it resembles an unrolled sheet.

The En-Gedi scroll was made from animal skin, which Seales says is better for contrast against the ink than papyrus, and also benefited from resolution that was twice as good as what he used in 2009. He sent his findings to Shore in 2015; she wrote him back an email humming with excitement. Seales didn’t know what he had uncovered—he doesn’t read Hebrew—but Shor did: It was the first two chapters of the Book of Leviticus, the earliest example of Bible text after the Dead Sea Scrolls themselves.

“When we saw the results we almost fainted,” Shor told reporters. “We had been certain it was just a shot in the dark.”

The fully unwrapped En-Gedi scroll with writing visible
The fully unwrapped En-Gedi scroll revealed writing that had not been seen in centuries.

Shor’s willingness to embrace new technology helped reveal text locked away for centuries. Conservators are notoriously cautious when it comes to handling such delicate relics—even though Seales never touches one personally, since curators are responsible for getting scrolls in and out of CT scanners. Only recently has Seales been able have more productive conversations at the Officina dei Papiri at the National Library of Naples in Italy, where the bulk of the Herculaneum scrolls are kept, and the University of Oxford. (The Institut de France and the British Library also hold Herculaneum scrolls.)

He remains optimistic that the method used for the En-Gedi material will work for the Herculaneum collection. At a conference this past March, he and members of his team presented new findings showing success in determining the column structure of one text (17 characters per line), as well as reading specific letters—and even entire names. Part of the breakthrough comes from high-powered x-ray beams like the one housed at Diamond Light Source in the UK, which are proving potent enough to isolate the trace amounts of lead in the ink.


The progress can seem glacial, but Seales has nonetheless gone from imaging a wrapped papyrus to isolating a clearly defined letter. Next, he hopes, will come sentences, possibly isolated by artificial intelligence software he's currently writing.

But even with permission, Seales’s pursuit of a viewable Herculaneum fragment is still dependent on funding. “I sometimes cringe when I see people say, ‘Seales has been working on this for two decades, unable to figure out the problem,’” he says. “Funding comes and goes.” Commercial applications for his software and methodology—like bone scanning or even virtual colonoscopy—could one day underwrite the academic work.

With access, cooperation, and a little luck, he remains optimistic we’ll eventually be able to uncover the knowledge long buried by Mount Vesuvius—time capsules that are slowly revealing their secrets, one micron at a time.

All images courtesy of University of Kentucky/Brent Seales.

15 Positively Reinforcing Facts About B.F. Skinner

Silly rabbit via Wikimedia Commons // CC BY 3.0
Silly rabbit via Wikimedia Commons // CC BY 3.0

Burrhus Frederic Skinner was one of the preeminent American psychologists of the 20th century. B.F. Skinner founded “radical behaviorism”—a twist on traditional behaviorism, a field of psychology that focused exclusively on observable human behavior. Thoughts, feelings, and perceptions were cast aside as unobservable.

B.F. Skinner dubbed his own method of observing behavior “operant conditioning,” which posited that behavior is determined solely by its consequences—either reinforcements or punishments. He also coined the term "positive reinforcement." 

To Skinner’s critics, the idea that these “principles of reinforcement,” as he called them, lead to easy “behavior modification” suggested that we do not have free will and are little more than automatons acting in response to stimuli. But his fans considered him visionary. Controversial to the end, B.F. Skinner was well known for his unconventional methods, unusual inventions, and utopian—some say dystopian—ideas about human society.

1. B.F. Skinner invented the "operant conditioning" or "Skinner" box.

Skinner believed that the best way to understand behavior is to look at the causes of an action and its consequences. He called this approach “operant conditioning.” Skinner began by studying rats interacting with an environment inside a box, where they were rewarded with a pellet of food for responding to a stimulus like light or sound with desired behavior. This simple experiment design would over the years take on dark metaphorical meaning: Any environment that had mechanisms in place to manipulate or control behavior could be called a "Skinner box." Recently, some have argued that social media is a sort of digital Skinner box: Likes, clicks, and shares are the pellet-like rewards we get for responding to our environment with certain behavior. Yes, we are the rats.

2. B.F. Skinner believed that all behavior was affected by one of three "operants."

Skinner proposed there were only three “operants” that had affected human behavior. Neutral operants were responses from the environment that had a benign effect on a behavior. Reinforcers were responses that increased the likelihood of a behavior’s repetition. And punishers decreased the likelihood of a behavior’s repetition. While he was correct that behavior can be modified via this system, it’s only one of many methods for doing so, and it failed to take into account how emotions, thoughts, and—as we learned eventually—the brain itself account for changes in behavior.

3. He's responsible for the term "positive reinforcement."

B.F. Skinner eventually moved on to studying pigeons in his Skinner box. The pigeons would peck at a disc to gain access to food at various intervals, and for completing certain tasks. From this Skinner concluded that some form of reinforcement was crucial in learning new behaviors. To his mind, positive reinforcement strengthens a behavior by providing a consequence an individual finds rewarding. He concluded that reinforced behavior tends to be repeated and strengthened.

4. Some critics felt "positive reinforcement" amounted to bribery.

Critics were dubious that Skinner's focus on behavior modification through positive reinforcement of desired behavior could actually change behavior for the long term, and that it was little more than temporary reward, like bribery, for a short-term behavioral change.

5. B.F. Skinner's idea of "negative reinforcement" isn't what you think.

Skinner believed negative reinforcement also helped to strengthen behavior; this doesn't mean exposing an animal or person to a negative stimulus, but rather removing an “unpleasant reinforcer.” The idea was that removing the negative stimulus would feel like a “reward” to the animal or person.

6. B.F. Skinner taught pigeons to play ping-pong.

As part of his research into positive reinforcement, he taught pigeons to play ping-pong as a first step in seeing how trainable they were. He ultimately wanted to teach them to guide bombs and missiles and even convinced the military to fund his research to that effect. He liked working with pigeons because they responded well to reinforcements and punishments, thus validating his theories. We know now that pigeons can be trained in a whole host of tasks, including distinguishing written words from nonsense and spotting cancer.

7. B.F. Skinner's first book, The Behavior of Organisms, broke new ground.

Published in 1938, Skinner’s debut book made the case that simple observation of cause and effect, reward and punishment, were as significant to understanding behavior as other “conceptual or neural processes.”

Skinner believed behavior was everything. Thoughts and feelings were just unreliable byproducts of behaviors, he argued—and therefore dismissed them. Many of his fellow psychologists disagreed. Regardless, Skinner’s theories contributed to a greater understanding of the relationship between stimuli and resulting behavior and may have even laid the groundwork for understanding the brain’s reward circuitry, which centers around the amygdala.

8. B.F. Skinner created the "baby tender."

Skinner was fond of inventions, and having children gave him a new outlet for his tendencies. He designed a special crib for his infant daughter called “the baby tender.” The clear box, with air holes, was heated so that the baby didn't need blankets. Unlike typical cribs, there were no slats in the sides, which he said prevented possible injury. Unsurprisingly, it did not catch on with the public.

9. B.F. Skinner also developed his own "teaching machine."

Silly rabbit via Wikimedia Commons // CC BY 3.0

You may have Skinner to thank for modern school workbooks and test-taking procedures. In 1954 Skinner visited his daughter’s classroom and found himself frustrated with the “inefficiencies” of the teaching procedures. His first "teaching machine"—a very basic program to improve teaching methods for spelling, math, and other school subjects—was little more than a fill-in-the-blank method on workbook or computer. It’s now considered a precursor to computer-assisted learning programs.

10. Skinner imaged an ideal society based on his theories of human behavior.

Skinner admired Henry David Thoreau’s famous book Walden, in which Thoreau writes about his retreat to the woods to get in greater contact with his inner nature. Skinner's "Ten Commandments" for a utopian world include: “(1) No way of life is inevitable. Examine your own closely. (2) If you do not like it, change it. (3) But do not try to change it through political action. Even if you succeed in gaining power, you will not likely be able to use it any more wisely than your predecessors. (4) Ask only to be left alone to solve your problems in your own way. (5) Simplify your needs. Learn how to be happy with fewer possessions.”

11. B.F. Skinner wrote a utopian novel, Walden Two.

Though inspired by Walden, Skinner also felt the book was too self-indulgent, so he wrote his own fictional follow-up with the 1948 novel Walden Two. The book proposed a type of utopian—some say dystopian—society that employed a system of behavior modification based on operant conditioning. This system of rewards and punishments would, Skinner proposed, make people into good citizens:

“We can achieve a sort of control under which the controlled, though they are following a code much more scrupulously than was ever the case under the old system, nevertheless feel free. They are doing what they want to do, not what they are forced to do. That's the source of the tremendous power of positive reinforcement—there's no restraint and no revolt. By careful cultural design, we control not the final behavior, but the inclination to behave—the motives, desires, the wishes.”

12. Some felt Skinner's ideas were reductionist ...

Critics, of which there were many, felt he reduced human behavior to a series of actions and reactions: that an individual human “mind” only existed in a social context, and that humans could be easily manipulated by external cues. He did not put much store in his critics. Even at age 83, just three years before he died, he told Daniel Goleman in a 1987 New York Times article, “I think cognitive psychology is a great hoax and a fraud, and that goes for brain science, too. They are nowhere near answering the important questions about behavior.”

13. ... and others were horrified by Walden Two.

Astronomer and colleague JK Jessup wrote, “Skinner's utopian vision could change the nature of Western civilization more disastrously than the nuclear physicists and biochemists combined.”

14. B.F. Skinner implied that humans had no free will or individual consciousness.

In the late 1960s and early '70s, Skinner wrote several works applying his behavioral theories to society, including Beyond Freedom and Dignity (1971). He drew fire for implying that humans had no free will or individual consciousness but could simply be controlled by reward and punishment. His critics shouldn't have been surprised: this was the very essence of his behaviorism. He, however, was unconcerned with criticism. His daughter Julie S. Vargas has written that “Skinner felt that by answering critics (a) you showed that their criticism affected you; and (b) you gave them attention, thus raising their reputation. So he left replies to others.”

15. He died convinced that the fate of humanity lay in applying his methods of behavioral science to society.

In 1990, he died of leukemia at age 86 after receiving a Lifetime Achievement Award from the American Psychological Association. Proud of his work, he was nonetheless concerned about the fate of humanity and worried “about daily life in Western culture, international conflict and peace, and why people were not acting to save the world.”

A New DNA Test Will Break Down Your Cat's Breed


Modern DNA testing kits can reveal a lot of information about you just by sending your spit off to a lab for analysis. As a result, it's easier than ever to learn about your personal ancestry and health risks. And now, the same goes for your cat, too.

Basepaws is now offering what it calls the "world's first DNA test for cats," which can tell you which breeds your beloved fur baby likely descended from, in addition to other information about their characteristics. The CatKit will reveal whether your little Simba is more similar to an American Shorthair, Abyssinian, or one of the other 30 breeds on record, as well as determining which of the "big cats" (think lions) your kitty has the most in common with.

Here's how it works: After receiving your kit in the mail, you will be asked to collect a DNA sample from your feline friend. The current kit includes adhesives for collecting cat hair, but Basepaws will soon roll out new kits that call for saliva samples instead. (This will provide a more consistent DNA sample, while also allowing staff to process more samples at once, according to a company spokesperson. It also will make it easier to collect samples from hairless cats like Sphinxes.)

A cat DNA test result

Once you collect the sample, just mail it in and wait eight to 12 weeks for your report. Basepaws uses sequencing machines to "read" your kitty's genetic code, comparing it to the sequences of other cats in its network. "More than 99 percent of your cat's genetic sequence will be similar to every other cat; it's the small differences that make your cat unique," Basepaws writes on its website.

In the future, Basepaws will also be able to determine your cat's predisposition for certain diseases, as well as their personality and physical traits. The company holds on to your cat's genetic data, allowing it to provide updates about your cat as the Basepaws database continues to grow.

Order a kit on the Basepaws website for $95. Enter the code "MEOWRCH-I5W3RH" at the checkout for a 10 percent discount.

And don't feel left out if you're a dog lover rather than a cat person—Wisdom Panel offers a similar service for canine companions. Its kit is available for $73 on Amazon.