Under the gold standard, a country’s money supply was linked to gold. The necessity of being able to convert fiat money into gold on demand strictly limited the amount of fiat money in circulation to a multiple of the central banks’ gold reserves, with most countries having legal minimum ratios of gold to notes/currency issued or other similar limits. International balance of payments differences were settled in gold. Countries with a balance of payments surplus would receive gold inflows, while countries in deficit would experience an outflow of gold.

In theory, international settlement in gold meant that the international monetary system based on the gold standard was self correcting. Namely, a country running a balance of payments deficit would experience an outflow of gold, a reduction in money supply, a decline in the domestic price level, a rise in competitiveness and, therefore, a correction in the balance of payments deficit. The reverse would be true for countries with a balance of payments surplus. This was the so called “price-specie flow mechanism” set out by 18th century philosopher and economist David Hume.

This was the underlying principle of how the gold standard operated, although in practice it was more complex. The adjustment process could be accelerated by central bank operations. The main tool was the discount rate (the rate at which the central bank would lend money to commercial banks or financial institutions) which would in turn influence market interest rates. A rise in interest rates would speed up the adjustment process through two channels. First, it would make borrowing more expensive, reducing investment spending and domestic demand, which in turn would put downward pressure on domestic prices, enhancing competitiveness and stimulating exports. Second, higher interest rates would attract money from abroad, improving the capital account of the balance of payments. A fall in interest rates would have the opposite effects. The central bank could also directly affect the amount of money in circulation by buying or selling domestic assets though this required deep financial markets and so was only done to a significant extent in the UK and, latterly, in Germany.

The use of such methods meant that any correction of an economic imbalance would be accelerated and it would not normally be necessary to wait for the point at which substantial quantities of gold needed to be transported from one country to another.