Oh, one I can answer! There’s a great book about this: Newton and the Counterfeiter
Basically, he is the reason there’s a pattern etched on the outside of most coins (knurling around a US quarter and the holes punched into 1 pound coins.) the reason being that there were large, well organized gangs who would take coins and shave off small amounts from the smooth edges of coins.
England was on a silver standard (Newton moved England to a de facto gold standard in 1717) so a coin was worth its exact weight. These gangs would gather the shavings from a bunch of coins to mint new, totally legit coins. So nearly all the coins in circulation were either not the value they were supposed to be or they were fake.
These gangs were so prolific that the entire economy was slowly collapsing because merchants couldn’t trust the coinage. If you can’t trust money, even today, everything will colapse. This is why Newton had counterfeiters hanged for their crimes. It was a public way of reestablishing trust in the economy.
But read the book. It’s amazing. This dude had his own army running around London. He would use disguises and often participate in busts and stakeouts. All with the full permission of the Crown.
In Neal Stephenson’s The Baroque Cycle (fiction) he proposes the silver in England was being stolen en masse by the French to devalue the economy. The French were on a gold standard and would sell the silver for gold to the Chinese who were also on a silver standard. So France got more gold (+) and damaged the economy of their main rival (++). Dunno if that’s true though.
auto correct, but this a great read about that time https://www.amazon.com/Newton-Counterfeiter-Detective-Greatest-Scientist/dp/0547336047
He became Master of the Royal Mint and prosecuted counterfeiters.
There is a Book about that with more information.