Newton and the Counterfeiter by Thomas Levenson

Who would have thought Isaac Newton - natural philosopher, theologian, would-be alchemist - would also have been a detective?  And arguably one of England's very first.

In the late 17th century the Royal Mint was a facing a crisis.  Strange to think now, but back then coins were actually worth their weight in gold.  Or, more often, silver.  This became a big problem when the price of silver started becoming more valuable on the continent.  Economists may be able to help me out, but I think this is because more gold was coming in to Spain and the rest of mainland Europe from South America, so silver could buy more gold across the channel.  This meant there was an actual shortage of silver to make coins, as well as the widespread clipping of coins and the equally widespread practise of counterfeiting.  In fact, one in five coins in circulation at this time was estimated to be fake.  None of this made King William happy, as he was running out of money to wage war against Louis XIV.

Newton was brought in as an all round braniac to sort things out, which he did admirably.  He figured out how deep in trouble were, and set about minting as many new coins as possible.  These had a milled edge, so they couldn't be clipped easily, and they were harder to counterfeit.  He also carried out possibly the world's first time and motion survey at the Mint - finding how fast the coins could be churned out before mistakes and accidents happened.  This not only increased production greatly, it cut the number of injuries to the workers.

But Newton didn't stop there - he also went after the counterfeiters by building up a network of spies and stool pigeons.  He frequented the seedy taverns himself to find out what was going on in the criminal underworld.  Not that all the counterfeiters were to be found in such lowly establishments - William Chaloner was the most brazen of the lot, and actually gave evidence to a House of Commons committee about how he was the man to sort out the problems at the mint.  He was pushing for a top position there himself, despite being the biggest faker of coins in London, and he was almost successful.  I won't give the rest of it away, but suffice it to say Isaac Newton knew how to hold a grudge, and he was man you messed with at your peril.

There's a lot of good research in this book - in large part because a "true crime" book about Chaloner was published shortly after his execution (spoiler.)  But I was especially interested in this topic because it's the background to much of Neal Stephenson's Baroque Trilogy, especially the final part System of the World.  This is where the modern world starts to take shape, with international markets, industrialisation and the seeds of modern banking.  And at the centre you've got the world's greatest scientist turned crimefighter!  Cracking stuff.