In Cantillon’s day, the basis of money was gold, so he wrote about what happened when a nation-state discovered a gold mine in its territory. Increasing the amount of gold in the realm would not just increase price levels, he observed, but would change who had wealth and he didn’t. As he put it, “doubling the quantity of money in a state, the prices of products and merchandise are not always doubled. The river, which runs and winds about in its bed, will not flow with double the speed when the amount of water is doubled.”
Cantillon went on to discuss how money would flow, basically noting that rich people near the mine would spend it on 18th century luxuries like servants and meat pies, prompting a general rise in prices. Eventually the money would get out to the populace, but until it did, working people would have to pay higher prices without access to the new money that mine owners had. So there would be inflation, with uneven distribution of purchasing power.
There’s also a China angle. Cantillon noted that a kingdom discovering gold would in the long-run erode its own manufacturing base, that the non-neutrality of money also had geopolitical consequences.
Here’s how he put it: