interest in limited contexts, such as currency boards. It is generally held in ill repute today, with Frederic Mishkin, a governor of the Federal Reserve going so far as to say it had been "completely discredited." The debate between currency, or quantity theory, and the banking schools during the 19th century prefigures current questions about the credibility of money in the present. In the 19th century, the banking schools had greater influence in policy in the United States and Great Britain, while the currency schools had more influence "on the continent", that is in non-British countries, particularly in the Latin Monetary Union and the Scandinavian Monetary Union. In 2019 monetary historians Thomas M. Humphrey and Richard H. Timberlake published "Gold, the Real Bills Doctrine, and the Fed: Sources of Monetary Disorder 1922-1938". Effects of inflation General effect Inflation is the decrease in the purchasing power of a currency. That is, when the general level of prices rise, each monetary unit can buy fewer goods and services in aggregate. The effect of inflation differs on different sectors of the economy, with some sectors being adversely affected while others benefitting. For example, with inflation, those segments in society which own physical assets, such as property, stock etc., benefit from the price/value of their holdings going up, when those who seek to acquire them will need to pay more for them. Their ability to do so will depend on the degree to which their income is fixed. For example, increases in payments to workers and pensioners often lag behind inflation, and for some people income is fixed. Also, individuals or institutions with cash assets will experience a decline in the purchasing power of the cash. Increases in the price level (inflation) erode the real value of money (the functional currency) and other items with an underlying monetary nature. Debtors who have debts with a fixed nominal rate of interest will see a reduction in the "real" interest rate as the inflation rate rises. The real interest on a loan is the nominal rate minus the inflation rate. The formula R = N-I approximates the correct answer as long as both the nominal interest rate and the inflation rate are small. The correct equation is r = n/i where r, n and i are expressed as ratios (e.g. 1.2 for +20%, 0.8 for −20%). As an example, when the inflation rate is 3%, a