under the price–specie flow mechanism proposed by economist David Hume wherein: Countries which exported more goods would receive specie (gold or silver) inflows, at the expense of countries which imported those goods. More specie in exporting countries will result in higher price levels there, and conversely in lower price levels amongst countries spending their specie. Price disparities will self-correct as lower prices in specie-deficient will attract spending from specie-rich countries, until price levels in both places equalize again. In practice, however, specie flows during the classical gold standard era failed to exhibit the self-corrective behavior described above. Gold finding its way back from surplus to deficit countries to exploit price differences was a painfully slow process, and central banks found it far more effective to raise or lower domestic price levels by lowering or raising domestic interest rates. High price level countries may raise interest rates to lower domestic demand and prices, but it may also trigger gold inflows from investors – contradicting the premise that gold will flow out of countries with high price levels. Developed economies deciding to buy or sell domestic assets to international investors also turned out to be more effective in influencing gold flows than the self-correcting mechanism predicted by Hume. Another set of violations to the "rules of the game" involved central banks not intervening in a timely manner even as exchange rates went outside the "gold points" (in the example above, cases existed of the pound climbing above 25.42 francs or falling below 25.02 francs). Central banks were found to pursue other objectives other than fixed exchange rates to gold (like e.g. lower domestic prices, or stopping huge gold outflows), though such behavior is limited by public credibility on their adherence to the gold standard. Keynes described such violations occurring before 1913 by French banks limiting gold payouts to 200 francs per head and charging a 1% premium, and by the German Reichsbank partially suspending free payment in gold, though "covertly and with shame". Some countries had limited success in implementing the gold standard even while disregarding such "rules of the game" in its pursuit of other monetary policy objectives. Inside the Latin Monetary Union, the Italian lira and the Spanish peseta traded outside typical gold-standard levels of 25.02–25.42F/£ for extended periods of time. Italy tolerated in 1866 the issuance of (forced legal tender paper currency) worth less than the Latin Monetary Union