Newton in 1702

In 1699, Isaac Newton was ready for a new challenge. It had taken months for the Warden of the Mint to build a watertight case to prosecute the most notorious counterfeiter in the land. His forensic analysis of the evidence and dogged determination to get his man had paid off. In March, Newton’s nemesis, William Chaloner, made a one way trip to the gallows at Tyburn to suffer the ultimate penalty for his crimes.

Pursuing and prosecuting criminals wasn’t a task that Newton particularly relished. Still, when he was told that it was part of his job description, he applied the same scientific rigour to his criminal investigations that he had applied to his theorems. In doing so, he became arguably London’s first undercover detective.

On 17th December 1699, the Master of the Mint Thomas Neale died, and Newton was offered the role. He accepted it on Christmas Day 1699, his 57th birthday. Though technically less senior than the Warden, it was a more lucrative post because the Master acted as a contractor to the Crown and profited from the rates at which work was put out to sub-contractors. Newton was to remain Master for the Mint until his death twenty-seven years later.

Once again, Newton threw himself into his new role, working diligently and with great integrity to improve the reputation of the Mint, which had been dogged for decades by accusations of corruption and incompetence. At a time when corruption was widespread, he set himself up as a role model for his employees to follow, as evidenced when he refused a bribe of over £6000 to award contracts for the procurement of copper.

Newton was determined to use the new minting technology available to him to create the best possible visual appearance of coins. He hired a skilled German jeweller from Dresden named John Croker to engrave designs onto the dies at a greater depth. The resulting die would then be used to strike coins in high relief, which would make the monarch’s portrait look more lifelike. The deeply engraved Two Guinea and Five Guinea pieces that were struck in 1701 are known today as the “fine work” Guineas. They are a testimony to Newton’s determination to produce the best possible coinage and have rightly become numismatic classics.

The ‘Fine Work’ Five Guinea

In April 1705, Queen Anne knighted Newton during a royal visit to Trinity College, Cambridge. The knighthood is likely to have been motivated by political considerations rather than recognition of his scientific discoveries or services as Master of the Mint. Nonetheless, Newton became only the second scientist to be knighted after Sir Francis Bacon.

Sir Isaac took his responsibilities as Master of the Mint very seriously and maintained an active involvement in its day-to-day affairs even into old age. The administrative skill he brought to the role is demonstrated in the hundreds of surviving reports and letters he wrote as Master. One of his most famous reports, issued in September 1717 to the Lords Commissioners of His Majesty’s Treasury, established a new mint ratio between silver and gold that had the effect of moving Britain onto the gold standard.

With silver coinage in such short supply, there was an urgent need to issue a lower denomination gold coin. In 1718 it was decided to strike a gold quarter guinea worth approximately the same as the five-shilling silver Crown. The new coin weighed 2.1 grams and was just 16 millimetres in diameter. Newton did not appreciate that such a small coin would be impractical to use, which made them unpopular. Of the 37,380 coins minted, many were put aside as keepsakes due to their beautifully intricate design. Production of the quarter guinea ceased within a year, and an increased number of guineas and half guineas were made instead.

The short lived Quarter Guinea, beautiful but too small for practical use

Newton was particularly concerned with the accuracy of the currency. He was determined to ensure that all coins were made to the correct weight and fineness, varying as little as possible. This level of accuracy was unprecedented. It is arguably one of his most outstanding achievements as Master of The Mint that he brought the coinage, in his own words, to a “much greater degree of exactness than was ever known before”.

Given his undisputed commitment to accuracy in every aspect of his work, it is hardly a surprise that Newton reacted furiously in 1710 at the judgement of the Trial of the Pyx, who ruled that his gold coins were below standard. Trials have been held in London on an annual basis from the Twelfth Century to the present day and are presided over by a judge with an expert jury of assayers. Their purpose is to test randomly selected newly minted coins to ensure that they are within the statutory limits for metallic composition, weight and size.

On this particular occasion, Newton was so adamant that his coins had been manufactured to the correct weight and finesse that the gold trial plate used by the assayers to evaluate the coins was itself evaluated and found to be below the legal standard. The coins themselves were perfect.

Knowing the penalty for failing the Trial of the Pyx makes Newton’s unwillingness to admit error quite understandable. It was more than professional pride. As Master of the Mint, he could be held directly accountable for any coins that failed the trial. Punishment ranged from imprisonment to hanging and quartering!

Despite his great ability with numbers and mathematical calculations, Newton still lost a fortune on the stock market. In 1720 he invested heavily in the South Sea Company, established in the early Eighteenth Century, which had a monopoly on trade in the South Seas. Newton initially purchased and sold a small number of shares and made an impressive profit. As he watched stock in the company continue to climb, Newton bought more shares, eventually pouring almost his entire life savings into the company. Then, he watched in horror as the bubble burst. According to his niece, he lost around £20,000 and is said to have remarked ruefully at the time, “I can calculate the movement of stars, but not the madness of men.”

Newton never married, and his chronic insecurity, bouts of depression and preoccupation with his work meant that few friends came to visit. Towards the end of his life, he lived near Winchester with his niece Catherine (Barton) Conduitt and her husband John. When asked, shortly before his death, how he would describe his achievements, he replied;

“I do not know what I may appear to the world; but to myself I seem to have been only like a boy playing on the seashore, and diverting myself now and then in finding a smoother pebble or prettier shell than ordinary, while the great ocean of truth lay all undiscovered before me.”

Sir Isaac Newton died on 31st March 1727, at the age of 84 and is buried at Westminster Abbey.

Given his lengthy association with coinage, it was inevitable that Newton would eventually be commemorated on one. Sixty years after his death, a severe shortage of farthings, half-pennies and pennies for everyday trade led to many private businesses taking matters into their own hands and minting large numbers of copper tokens. Workers were paid in tokens and would exchange them locally for goods and services in company-owned shops. By the end of the Eighteenth Century, millions of tokens had been struck and were in everyday use throughout Great Britain.

Half-penny copper token depicting Newton in 1793

In 1793, copper farthings and half-penny tokens featuring Newton on the obverse proved very popular. The reverse depicted a horn of plenty (cornucopia), a symbol of abundance that honours his outstanding contribution to science, astronomy and mathematics. The half-penny is larger, and in addition to the cornucopia also depicts the Caduceus, the staff carried by Hermes, the winged messenger of the Gods. This is a symbol of communication, writing, printing, eloquence, enlightenment and understanding. The inclusion of the symbols made the Newton tokens very popular, not least because they were believed to grant prosperity and eloquence to anyone who owned them

Nearly two hundred years later in 1978, the Bank of England honoured Sir Isaac Newton on the reverse of the one-pound note. The design, by Harry Eccleston, featured the Caduceus and cornucopia adjacent to Queen Elizabeth II on the front. The reverse depicted Newton holding an open book seated next to a prism and a reflecting telescope. Behind him is the heliocentric solar system, reflecting the enormous impact that his single-minded determination to uncover the secrets of the universe has had on the ongoing development of humanity.

Newton appeared on the British one pound banknote from 1978 to 1988

In 2017, The Royal Mint commemorated the life of their most famous Mint Master with a fifty pence coin that borrowed the design of the solar system that had featured on the old banknote. The Government of Gibraltar also issued a commemorative Quarter Guinea and Five Guinea in the same year to honour Newton’s ‘fine work’. The new design incorporated the cornucopia and the Caduceus, together with an apple, which Newton famously credited with helping him develop the theory of gravity after watching one fall from a tree outside his home.

Commemorative gold Five Guineas issued by Gibraltar in 2017