I was working in the faculty room yesterday when one of the instructors asked the open air, “Does anyone know anything about Newtonian physics?” I told him his question was coincidental, because I had just finished reading a  book about Isaac Newton, the 17th century physicist, mathematician, and natural philosopher.

I think I correctly answered my colleague’s question, which had to do with Newton’s Second Law of Motion: “A change in motion is proportional to the motive force impressed and takes place along the straight line in which that force is impressed.” But while the book I just read explained the achievements for which Newton is still regarded as one of the greatest of geniuses, its purpose is to recount the work of his later life, when he was warden of the Royal Mint — and particularly the relentless detective work with which he brought to justice Britain’s most brazen counterfeiter.

Statue of Isaac Newton - and the apple - at the Oxford Museum of Natural History

Newton did his signature scientific work at Trinity College in Cambridge, but he lobbied friends for many years to get him a political appointment in London. It finally came in the form of position at the mint, which made the silver coins that were Britain’s only hard currency at the time. When Newton arrived at his office in the Tower of London, the kingdom’s economy was on the verge of collapse, partly because  of expensive military operations undertaken by William of Orange and partly because the royal currency was, in a word, disappearing. An old issue of coins was being degraded by so-called “clippers” who shaved bits of silver from the money to be melted down and sold. Meanwhile British silver was leaving the country altogether because it was worth more in exchange for gold in other countries than it was in exchange for commodities in England. The result was a bull market for counterfeiters, including the audacious and dangerous William Chaloner.

Newton’s predecessors as warden of the mint had not taken the job seriously except as a source of income, and that was expected of Newton, too. But he applied to the mint the same combination of energy and curiosity that had fueled his discoveries in fields like gravity and the behavior of light and his development of the mathematical system known as the calculus.

Isaac Newton's image on a one-pound note

First, Newton took control of a program already underway when he arrived – the recall and replacement of all British coins then in circulation. This project was limping along when Newton took over, and he put the means in place to accelerate it and get the job done in a fraction of the projected time. Then he turned his attention to the counterfeiters, employing a network of spies and informers and counter-agents and double crossers to gather information and pounce on “coiners” – eventually including Chaloner, whose career as a counterfeiter had had its ups and downs.

Isaac Newton investigates the refraction of light.

Like most such scoundrels, Chaloner made his share of mistakes, and one of them was to publicly claim that the heart of the nation’s counterfeiting problem was in the mint itself, and imply that Newton’s incompetence was partly to blame. Don’t knock the Rock. Newton went after Chaloner with a vengeance, spending hundreds of hours personally interrogating people who could help build a case against the fraud. Chaloner had been in and out of prison several times and had dodged the noose that was reserved for counterfeiters, whom British law regarded as traitors. In Newton, he had met his match and – ultimately – his maker.

“Newton and the Counterfeiter,” both informative and entertaining, was written by Thomas Levenson, who is a professor of science writing at MIT.

A topic that Levenson discusses throughout this book – in fact, it’s an important thread that runs through all of Newton’s activities – is Newton’s search for contact with God. In fact, Levenson reports that religious matters became the preoccupation of Newton’s life when he had put most scientific inquiry behind him. I discussed that aspect of the book in a column in the Catholic Spirit, and it’s available at THIS LINK.