@augustus I think the point of specie-flow-mechanism is that it is a natural fail-safe mechanism in the gold standard, so even if the banks and speculators did nothing to bring the real world gold/currency exchange rate back to the peg, the act of physically moving the gold around would. Of course that is expensive, so people rather used different mechanisms, like short selling, to quickly restore the peg. But that doesn't mean that the specie-flow mechanism doesn't work, it's still the ultimate cause for the other mechanisms were preferred in real life.