Isaac Newton, pictured in 1689

In 1693, fifty-one-old Isaac Newton was mentally exhausted. After firmly rejecting a career in the family farming business as a young man, he had instead written the laws of motion, explained orbital mechanics, investigated the principles of light and colour and developed the calculus. His place in history as one of the greatest thinkers of the modern age was assured.

Newton had grown bored with his sedentary life as a Professor at Cambridge University. The man who had once pushed a bodkin into his eye to test his theories about colour now found that the scientific pursuit of truth no longer held the appeal it once did. His finest achievements were, he felt, behind him, and his behaviour had become increasingly unpredictable and erratic. He would fly into furious rages and write angry, vengeful letters to former friends accusing them of betrayal and conspiracy at the slightest provocation. Plagued by depression, paranoia and insomnia, he suffered what he would later describe as his ‘black year’. It would last eighteen months.

Newton needed a change of scene and a new challenge to exercise his mind. After a while, he began to bombard his friend Charles Montagu, Chancellor of the Exchequer, with letters requesting work in London. Eventually, on 19th March 1696, he received a reply, notifying him that he had been recommended for the position of Warden of the Royal Mint. Newton eagerly accepted and had reported for duty within the month.

Based at the Tower of London where the Mint made the coins of the realm, the Warden’s job was to enforce laws against counterfeiting. The office had been viewed as a largely symbolic position that required little work. However, Newton took the role extremely seriously and relished the challenge. Whether Montague intended it that way or not, his decision to allow Newton to apply his scientific methodology and towering intellect to the currency crisis was to prove an inspired one.

The Tower of London, pictured in 1737

Counterfeiting was a thriving industry in Britain when Newton arrived at the Tower of London to take up his new position. Around ten per cent of coins in circulation were fakes, cast or stamped from forged or stolen moulds and dies. In addition, the value of silver on the continent was greater than its face value on coins. As a result, huge numbers of silver coins were withdrawn from circulation, melted and taken abroad to be sold at a tidy profit. Genuine coins were often hoarded, thus proving Gresham’s law that “bad money drives out good”.

Counterfeiters would clip metal from coins (left) and use the clippings to make new coins (right).
Some counterfeit coins, such as those produced by William Chaloner, were of exceptionally high quality

Newton’s solution to the problem involved a Great Recoinage. This enormous operation involved taking in millions of pounds of coins by weight and re-minting them at their correct value. He organised a production line of 500 men at the Tower of London, and over the next four years, they smelted most of England’s money supply. To assist them, branch mints were established at Bristol, Chester, Exeter, Norwich, and York. Knowing that some counterfeiters had access to stolen Royal Mint equipment, Newton told the officers at these country mints to “trust not the computations of a single Clerk nor any other eyes than your own.”

On Newton’s orders, Mint employees worked six days a week from 4 a.m. to midnight. Before he arrived, no one thought the Mint could produce 15,000 coins in a week. Newton soon had them turning out 50,000 coins every week, and between 1696 and 1699, the value of silver struck was over £5.1 million, compared to £3.3million coined in the preceding 35 years.

Newton’s position as Warden of the Mint also meant that it was his responsibility to track down and prosecute counterfeiters. Chasing crooks was not something that particularly appealed to him, and he wrote a letter to the Treasury asking if he could be excused this particular duty. They reminded him that it was part of his job description, and so he set to work with his customary zeal and single-minded determination. To assist him, Parliament passed the Coin Act in 1696, making it an act of treason to make coins, construct, sell or possess the equipment required to make coins or assist anyone making coins. The punishment for doing so was death.

Newton was now able to devote more time to his primary duty of investigating and bringing to justice the counterfeiters and clippers. He went undercover himself and visited notorious bars, taverns and other dens of iniquity in London where criminals gathered to recruit informants and purchase information.

Newton went to bars and taverns gather evidence

Newton hired private “thief-takers” to locate counterfeiters and their equipment. Records show that he personally tracked criminals to their lairs and interrogated them in person. He became a regular visitor at the rat-infested Newgate Prison, where he conducted more than 58 interviews. Between June 1698 and December 1699, he conducted more than 100 cross-examinations of witnesses, informers, and suspects to build watertight cases against the accused. Newton gathered evidence to successfully prosecute 28 counterfeiters, most of whom went to the gallows and paid the ultimate penalty for their crimes

However, Newton’s biggest challenge was to prosecute the most prolific counterfeiter of the age. It took Newton many months to build a successful case against this kingpin of the criminal underworld, and soon he was working full time on this one goal. Like Sherlock Holmes and Moriarty, every great detective needs a worthy adversary. Newton’s was a man called William Chaloner, a resourceful and cunning counterfeiter of exceptional ability with ambitions to run The Royal Mint.

Chaloner was born in poverty, the son of a weaver in Lincolnshire. He ran away to London as a young man and started at the very bottom of the criminal ladder, hawking and scamming unwary passers-by on street corners. He possessed an enquiring mind and the gift of the gab and sometimes pretended to be a doctor to sell remedies for imaginary ailments that he would diagnose on the spot.

To provide a legitimate front for his business dealings, Chaloner set himself up as a recoverer of stolen property. Of course, he was able to do this because he had arranged for the property to be stolen in the first place. He also had a brief career informing on enemies of the state, paying Jacobites to print dissident literature and then betraying them to the authorities and pocketing the reward money. Eventually, his luck ran out, and he was named a suspect in a burglary case in 1690, which forced him to flee and go into hiding.

It was a chance meeting with a craftsman who showed him how to gild surfaces that made Chaloner’s fortune but ultimately took him to the gallows. He quickly realised the potential for counterfeiting gold and silver money, and over a lucrative eight-year career, he is believed to have counterfeited over £30,000 worth of currency.

Counterfeiting made Chaloner a very wealthy man. He bought a large house in the semi-rural suburb of Knightsbridge, rode in a carriage, wore fine clothes and presented himself to high society as a gentleman. After forging “Birmingham Groats”, he moved on to more lucrative Guineas, French Pistoles, crowns and half-crowns, Banknotes and lottery tickets

Chaloner developed a sophisticated casting method that involved pouring molten metal into high-quality brass moulds and set up a factory in Egham 20 miles outside London. It was said that he was so pleased with the quality of the counterfeits he was producing that it upset him to see them used as it spoiled their perfection!

Chancellor of the Exchequer, Charles Montagu, who appointed Newton the Warden of the Mint

Ultimately, Chaloner’s giant ego was his undoing. A few months before Newton took up his post, Chaloner had written to the Government claiming to have evidence that men working at the Mint were selling duplicates of the casts used to make coins. Of course, he didn’t tell them that he only knew this because he had purchased one of these casts for himself! When Newton heard of the letter, he immediately launched an investigation and interviewed more than 30 suspects to determine whether there was any truth in the accusations. Meanwhile, Chaloner tried to involve himself in the investigation and revealed his real purpose for writing the letter. He wanted Parliament to let him run the Royal Mint to sort out the mess!

Chaloner wrote letters, published pamphlets and was even invited to appear before Parliamentary committees, arguing that only he could solve England’s counterfeiting problem. He even went so far as to publicly accuse Newton of incompetence and possibly even fraud in managing the Great Recoinage. Newton was furious at this slur on his reputation, and so began a game of cat-and-mouse in which Chaloner sought to persuade Parliament to give him control of the Mint while Newton secretly compiled evidence to expose him as the chief counterfeiter in England.

Newton discovered that Chaloner had been arrested repeatedly for various scams and had even served time in jail for petty offences. However, because there were no centralised criminal records at the time, it had been easy for him to move from place to place and start again each time he was released. Astonishingly, Newton discovered that in 1694, Chaloner had been caught red-handed in the act of forging banknotes. He had talked his way out of prosecution on that occasion by naming people who he claimed were the real counterfeiters behind the operation. He even ended up receiving a reward for his information!

Much to Newton’s frustration, in 1697, Parliament ordered him to provide Chaloner with the resources to make prototypes of a new currency that he had proposed to them. Newton refused, so Chaloner went ahead and made them anyway using stolen casts. When Newton found out through his informer network, he immediately had Chaloner arrested. Chaloner quickly paid a key witness to flee to Scotland, and without him, the case against him collapsed. Newton then went to Parliament to voice his suspicions about Chaloner, but these were dismissed, and Chaloner went back to offering his services to run the Royal Mint, whilst simultaneously producing forged £50 banknotes and lottery tickets!

After that, Newton dedicated himself solely to the task of building a robust case against Chaloner. He worked relentlessly and with a single-minded determination to gather evidence for the prosecution. He methodically bribed, threatened and bullied witnesses for information that would allow his spies and informants to infiltrate Chaloner’s sophisticated counterfeiting operation. Eventually, there was enough evidence to arrest him again, and this time Newton even arranged for informants to be locked up with him to report back on anything that he said in custody.

Newgate Prison

When the trial finally came, Newton assembled eight witnesses to testify against Chaloner, including the wife of the man he had paid to run away to Scotland. She was willing to speak in court because Chaloner had scammed them out of money as well. Such was the weight of evidence against him that the jury quickly reached their verdict and sentenced the counterfeiter to hang.

Chaloner appealed for mercy from his condemned cell in Newgate Prison and wrote to Newton several times, begging him to save his life. His final letter concluded with the piteous words; “Oh dear Sir nobody can save me but you. O God my God I shall be murdered unless you save me.” Newton did not respond.

On 22nd March 1699, there was nothing left for Newton’s great adversary to do but protest to the people who had come to watch him hang at Tyburn that “he was murder’d … under pretence of Law”. He suffered a miserable death choking for several minutes at the end of the rope, much to the amusement of the jeering crowd.

The Tyburn tree, where Chaloner met his grisly fate in 1699

It is doubtful that Newton was at Tyburn that day to witness this culmination of months of hard work. In his notebook, he wrote simply that “Chaloner could have lived a long, honest life had he let the money and Government alone.”