The Mysterious Skeletons in Ben Franklin's Basement

Born in Boston in 1706, Benjamin Franklin was the 15th child of Josiah Franklin, a twice-married candlemaker. During his lifetime, he invented a flexible urinary catheter, bifocals and a style of wooden "swim fins."

He also established the first (formally organized) all-volunteer fire department in the American Colonies, helped negotiate the 1783 Treaty of Paris that ended the Revolutionary War and worked on the Declaration of Independence.

In addition, Franklin was a humorist, a deist, an early abolitionist, ambassador to France and the president of Pennsylvania's Supreme Executive Council (a role similar to governor).

Clearly his legacy is well-earned, but did Franklin have a dark side, too?

He was a well-known philanderer, complaining about his libido in print. He is known to have taken "air baths," where he'd open his windows and stand around naked, regardless of his neighbors' prying eyes.

And the man liked his liquor; he wrote and published "The Drinker's Dictionary" in 1737. It's composed of hundreds of slang terms for signaling that "a man is drunk."

But it's his affiliation with the Freemasons that often raises eyebrows. He helped one Pennsylvania chapter draft its bylaws and eventually became a Grandmaster.

Masons, in turn, have been the focus of some wild conspiracy theories. One of which claims that their organization has ties to the Illuminati, a group of ultra-powerful people who supposedly run the world in secret.

Let the record show that Franklin himself wasn't great at keeping secrets.

During the Revolution, he served as the head of an American diplomatic commission in Paris. On his watch, secret documents were left out in plain view, and the group had a bad habit of talking classified in public. Even worse, their secretary turned out to be a mole for the British.

Since Franklin dropped the ball on counterintelligence and failed to guard classified information, it's hard to believe he was part of a shadowy, super-secret cabal like the Illuminati or the Lizard People — as some conspiracy theorists maintain.

What is indisputable about Ben Franklin is he had bones in his basement. Human bones. Lots of human bones.

They were discovered in 1998 when an organization called Friends of Benjamin Franklin House decided to restore the four-story Georgian house in London where Franklin lived while he was an ambassador for the American Colonies.

It is the only location still standing where Franklin actually resided; he called the place home from 1757 to 1775.

During the late '90s restoration project, construction worker Jim Field found something in a window-free basement room: a human thigh bone.

The police were called to the scene, where more than 1,200 more bones ultimately emerged.

They'd been buried in a pit measuring 3.28 feet wide by 3.28 feet deep (1 meter wide by 1 meter deep). Back in Franklin's day, this bonebed would've been located underneath his garden.

Forensic analysis proved the bones were anything but fresh. A biologist at the University of London dated the remains to the mid-18th century, making them more than 200 years old.

In other words, they were buried around the same time Franklin lived in the house.

So where did the bones come from?

As the Benjamin Franklin House website reports, "The human remains derive from over 15 individuals and show dissection marks from surgical instruments." For example, someone had obviously taken a trepanning device and drilled holes into skull bones.

That "someone" was probably William Hewson.

A British physiologist and anatomist, Hewson married the daughter of Franklin's London landlady in 1770. The two men were not only neighbors, but friends as well.

Like the American founder, Hewson made a name for himself in scientific circles. His most famous experiment involved a dead sea turtle, which he injected with mercury to learn more about how the lymphatic system works. (Human beings share this system with other creatures.)

Hewson's background gave investigators the smoking gun they'd been after.

Not all the remains interred at the Benjamin Franklin House were human. Sea turtle bones were also removed from the pit. And what do you know? One of those turtle parts — a shell fragment — contained a small bead of mercury.

Forensic and historical evidence all but confirms that Hewson was the man responsible for this bone bit. But the question remains: Why would he leave body parts — human and otherwise — buried around Franklin's house? 

Consider the state of medical science at the time.

In 1772, Hewson founded an anatomy school at the building owned by his mother-in-law, which also happened to be Franklin's home. The school stayed open until 1778.

Future physicians needed to hone their craft by dissecting corpses. However, there were strict laws about cadaver usage. The only dead bodies educators could legally use were those of criminals who'd been hanged at the gallows.

Demand far outpaced supply. Getting a corpse by legal means could be a difficult process. So many teachers and students sidestepped the law by enlisting grave robbers to provide bodies they could dissect.

Over the wall of Franklin's garden, there was a gallows where public hangings were regularly conducted.

But it's not unreasonable to think Hewson landed specimens for his anatomy school through illegal grave robbing. And of course, if he used stolen corpses, Hewson would've had to ditch the evidence in secret. Hence the need for a private burial site.

William Hewson died in 1774; while dissecting a corpse, he accidentally cut himself and died from the infected wound. It's unclear if Benjamin Franklin ever knew what the younger man was up to in that English garden. With everything that was unfolding across the Atlantic, he certainly had a lot on his mind.