Here’s an image – the world’s greatest scientist is in a grubby London dive, talking to lowlifes.   Candles flicker on the table between them, and the air is close and foul.  He’s interrogating them closely, sometimes smiling and handing over a payment for information, and sometimes threatening them with Newgate Gaol. He’s a lean man of middle age and ordinary dress.  The most striking thing about him are his eyes.  It’s a gaze that cracked The System of the World, and now it’s directed at a web of crime that is undermining the nation.

Newton looking like an elven lord, Godfrey Kneller, 1689

It’s 1697, and Isaac Newton has just saved the English economy.  He organized the re-coinage that brought sound money back into circulation, and did it a year ahead of schedule.  In the previous year he had become Master of the Mint, the person in charge of actually creating money.  Now he’s fulfilling the other half of his duties and is tracking counterfeiters.  He has gone into pubs and taverns looking for information. Counterfeiting is a capital crime, and Newton has the authority to arrest.

He’s up against a supervillain amongst Coyners, one William Chaloner, who has not only been poisoning the country’s supply of silver coins, but is now starting to fake the new paper money as well.  If he succeeds, the newly formed Bank of England is doomed, and the King will be bankrupt.

Chaloner has slipped the noose several times by betraying his fellow counterfeiters, and has even won bounties for ratting them out on schemes that he himself had set up.  He has testified in front of Parliament that the Mint is corrupt, that people there are selling the high-tech secrets of how to make coins with milled edges.  He says that the Mint’s naive new Master is incapable of dealing with the problem, and puts himself forward as the one to clean it up. Little does he realize who he has come up against.

Juicy!  The story is told in “Newton and the Counterfeiter: the Unknown Detective Career of the World’s Greatest Scientist”, by Thomas Levenson, Houghton-Mifflin, 2009.   Levenson is a documentary producer (most notably of “Nova”), and a professor of science writing at MIT.  Oddly enough, his last book, “Einstein in Berlin”, was also about a great scientist in a difficult middle age.

He gives a quick rundown of Newton’s career: his loveless childhood, his solitary and total absorption in mathematics, physics, and alchemy during his time at Cambridge, and his bursting onto the world stage with the publication of “Philosophiæ Naturalis Principia Mathematica” in 1687, when he was 44.

The ideas in “Principia” had come to Newton 21 years earlier when he had returned home from Cambridge because of the plague.   He had worked them out in some detail, but did not bother to tell anyone.  As the Lucasian Professor at Cambridge his only duty was to give a course of lectures once every three terms, and those were often unattended.   He might have died in obscurity were it not for a chance visit in 1684 by Edmond Halley, the astronomer.   Halley asked him to settle a bet between him, Robert Hooke, and Christopher Wren – what kind of curve would describe the motion of the planets if they were drawn to the sun by some kind of attraction proportional to the inverse square of the distance.  “An ellipse,” said Newton.  How could he be so sure?  “Why, I have calculated it,” Newton replied, and several months later sent Halley his first major work, “De motu corporam in gyram”, “On the Motion of Bodies in Orbit”.  Halley pressed him for more, and three years later received the manuscript of “Principia”.   He had it published in London, where it sold out immediately and soon became a sensation.

Newton’s quiet life was over.  He became swept up in the rebellion against King James II known as the Glorious Revolution in 1689, and even served as an MP for a year when William of Orange came to power.   In the early 1690s he had what appears to be the only romance in his life, a passionate attachment to a young Swiss mathematician, Nicolas Fatio de Duillier.

Yet in 1693, at age 50, things fell apart for him.  Fatio stopped replying to his letters.  He abandoned the alchemy lab where he had spent 20 years of  work and had written millions of words of notes.   He became sick of the small world of Cambridge, and tired of living on only a hundred pounds a year.   He needed a new job.

Fortunately, he had an influential admirer – the doctor, courtier and philosopher John Locke.   Locke knew that the Crown was facing a near impossible problem – England’s money had become hopelessly corrupt – and put Newton’s name forward as the man to fix it.  He recommended him for the post of Master of the Mint, and Newton took the job in 1696.

Why on earth would someone like Newton be needed for such a bureaucratic position?   Because England’s currency was in a desperate state.  It was completely based on the weight of silver and gold coins, and yet people routinely clipped the edges off of them and melted down the fragments while passing off the coins as full weight.  The Mint had gone over to coins with milled edges some years earlier (which was made possible by stronger presses), and those could not be clipped (because that would damage the ridge on the coin’s edge) , but there was still a lot of the old money around.   The entire stock of coins in the land needed to be gathered in and re-issued in a more secure form, but the Warden of the Mint, Thomas Neale, was a fool, and no one could be found to manage the process.

Newton set to it.  He first read through decades of Mint records to find out where all the money came from.  That task alone would have killed you or I.  Then he re-organized the minting process itself by installing more presses, putting the machines in the right order and training people properly.   People had expected the re-coinage to take three years, and he did it in two.

The story so far is fairly well known.  Where Levenson has done new research is in Newton’s other major duty as Master – to stop counterfeiting.  Levenson has tracked down all the information he could find on Chaloner, and read through Newton’s own notes and bills.  A lot of the papers from this period appear to have been destroyed by Newton himself, indicating that unsavory things were done.

The key to breaking counterfeiting rings was to get credible testimony.   Because the penalty for it was so stiff, defendants were eager to testify against each other.  As a result, it was hard to persuade a jury that anyone was telling the truth.  In order to convict someone who was as intimately familiar with the system as Chaloner, Newton needed an ironclad chain of informers that would connect him with the crimes.  He set up a network of spies, but did a lot of the roaming of the London underworld himself.

You can probably guess how this particular thriller turns out, but I won’t spoil it.  It’s a great story, and Levenson appears to have researched it thoroughly.  I hope they get Jonathan Pryce for the movie adaptation!