Isaac Newton Was the World’s Original Counterfeiter Cop

Here’s the story of how the famous physicist played detective to capture his era’s most notorious currency faker

Sir Isaac Newton may be a renowned scientist whose name, like Einstein’s, works as a synonym for “genius.” But reducing him to a guy who sat under an apple tree musing about the notion of gravity for most of his days misses out on some of the physicist’s truly strange other interests. The man had darker, and more chaotic, aspects to his personality. For most of his life he was more obsessed with alchemy and divining hidden codes in the Bible than what we now call physics; he also spent a significant number of years hunting down and executing people.

If Newton loved being a cop (and he did), then this story is about his very own Moriarty — a man named William Chaloner.

In 1696 — a decade after the publication of the Principia but still a decade before Queen Anne would knight him — Newton was made a warden of the Royal Mint. Based in the Tower of London, the Mint made the coins of the realm. Technically, the warden’s job was to enforce laws against counterfeiting, but the office had long been seen as a cushy, symbolic position that aristocrats awarded to their political allies. Plenty of other marshals and magistrates already investigated counterfeiting independently, but Newton didn’t care. He was bored in Cambridge and wanted a new challenge from a job in London. After pestering the Chancellor of the Exchequer, Charles Montagu, 1st Earl of Halifax, he was given the warden role. Unenthused by the expectation that he’d delegate his responsibilities to deputies, he did something none of the other wardens had in the history of the job — he showed up to work.

Counterfeiting near the end of the 17th century provided plenty of problems to keep him occupied. By 1696, 10 percent of England’s coins were known to be fake—cast or stamped from forged or stolen moulds; and coin clipping, in which the edges of coins were shaved off and used to make new coins, was rampant. The face value of an English coin didn’t match its bullion value, and coins were being shipped, en masse, to other European cities like Paris and Madrid and sold on the metals markets there. Newton had the solution: In this case it meant a Great Recoinage—or taking in millions of pounds of coins by weight and re-minting them at their correct values. He organized a production line of 500 men at the Tower of London, smelting much of England’s money supply over a four-year period. Parliament also passed the Coin Act in 1696, making it illegal to sell or own the equipment needed to make coins. The punishment for counterfeiting was death.

All the while, when Newton first arrived to the Mint to assume his role as chief investigator, he found himself walking into a web of conspiracy theories and allegations of corruption—all stirred up by William Chaloner.

Chaloner was born somewhere in rural Warwickshire, in England’s Midlands. He apprenticed as a nail maker but quickly found he had talent as a forger of groats (a whimsical English name for a type of small-denomination coin). In the 1680s he landed in London, where he used his knack for salesmanship and quick talking (or “tongue pudding”) to peddle tin watches with hidden sex toys inside to the frustrated wives of the capital’s elite. He likewise sold a number of quack medical products and even had a brief career informing on enemies of the state, paying Jacobites to print copies of dissident literature and then leading the police straight to their doors, claiming the reward for their captures.

A few months before Newton arrived at the Mint, Chaloner had written a letter to the Lords Justices, the council of aristocrats ruling the country while William III was fighting in the Nine Years’ War. In it he claimed to have evidence that many of the men working at the Mint had sold copies of the casts used to make coins to counterfeiters, setting off a chain of accusations and counter-accusations from both Mint officials and people in prison on charges of forging coins. (Chaloner, of course, knew all this because he was one of the people who had bought one of the illicit casts.) Newton went into full detective-mode, personally interviewing as many as 30 different suspects and witnesses to try and untangle the mess — using a procedural technique derived from the scientific method.

He became expert at getting them to turn against each other by offering the possibility of escaping the death penalty — not that he had many qualms about sending people to the gallows. As historian John Craig wrote in an article for the Royal Society’s Notes and Records: “Newton was disinclined to mercy, except for the receipt of information of value, on the ground that these dogs always returned to their vomit.” Thus, he began to build up a network of informants throughout London’s criminal underworld.

Meanwhile, Chaloner had been working for several years as one of (if not the) most prolific coin forger in the country — at one point he claimed to have forged more than 30,000 golden Guineas throughout his career. So why had he written that letter setting off a conspiracy panic? Simple: He wanted a job at the Mint. Specifically, he wanted to be in charge of it.

The next few years saw a cat-and-mouse game between Chaloner and Newton — the former escaping jail and trying to convince Parliament to give him the job of designing and producing England’s money, while the latter (perhaps the only one who was entirely aware that Chaloner was a crook) tried to stop him.

With the profits of his counterfeiting business Chaloner had successfully built his image as one of a noble gentleman. Wearing the finest clothes and riding around in his own carriage, he wrote letters, published pamphlets, and appeared in front of committees at Parliament arguing that he could solve England’s counterfeiting problem. He proposed using the finest metalworking techniques to design unforgeable new coins, and keeping tabs on those traitors who were selling moulds to common criminals.

That was the William Chaloner the authorities knew; Newton saw him differently. While Chaloner had been arrested repeatedly over the years for various scams and even served short sentences in jail, there were no centralized criminal records at the time—so it was relatively easy for him to slip from place to place and start anew once he was released. He was also adept at shirking prison time. Once, in 1694, he set up shop forging then-new Bank of England banknotes; when he was caught, he not only got away by naming accomplices but received a tidy reward for it as well.

In 1697, Parliament ordered Newton to provide Chaloner with the resources to make prototypes of the newly designed coins he had proposed. Aware of Chaloner’s history but lacking proof, Newton refused. He knew that the design features Chaloner was suggesting were expensive and useless, and that his long-term goal was to get himself into a position that made it possible to help his criminal colleagues counterfeit more easily.

Chaloner set up in a country house a few miles outside of London with some stolen casts to make the new coins anyway. When Newton found this out through his informer network, he had him arrested. Before a conviction could be rendered, though, Chaloner paid key witness Thomas Holloway to flee to Scotland until the case against him collapsed. Even more ridiculous, after Newton presented a report to Parliament detailing the scandal, its members dismissed the accusations and Chaloner went straight back to asking for a job at the Mint — all the while launching a new scheme forging £50 notes and lottery tickets.

Newton was furious. He wanted Chaloner hanged. So, he went about constructing an airtight case, using his network of informants and spies around London in methodical fashion to build a comprehensive picture of Chaloner’s movements and activities over the previous 18 months. He even went undercover himself to gather evidence from witnesses at pubs around the city. When the trial finally came, he had eight witnesses, including the wife of the man Chaloner had paid to run away to Scotland. (Turns out, he’d scammed them out of money as well.)

The treason charge stuck, and on a cold, damp March day in 1699, Chaloner was hanged in Tyburn. Later that year, Newton was made the master of the Royal Mint, a position he would hold until his death in 1727.

If you’d like to read an even more in-depth version of this story, make sure to check out Thomas Leveson’s 2009 book, Newton and the Counterfeiter.