arose under the pressures of war and rapid technological change. In any case, prices had not reached equilibrium by the time of the Great Depression, which served to kill off the system completely. For example, Germany had gone off the gold standard in 1914, and could not effectively return to it because war reparations had cost it much of its gold reserves. During the occupation of the Ruhr the German central bank (Reichsbank) issued enormous sums of non-convertible marks to support workers who were on strike against the French occupation and to buy foreign currency for reparations; this led to the German hyperinflation of the early 1920s and the decimation of the German middle class. The U.S. did not suspend the gold standard during the war. The newly created Federal Reserve intervened in currency markets and sold bonds to "sterilize" some of the gold imports that would have otherwise increased the stock of money. By 1927 many countries had returned to the gold standard. As a result of World War I the United States, which had been a net debtor country, had become a net creditor by 1919. Interwar period The gold specie standard ended in the United Kingdom and the rest of the British Empire at the outbreak of World War I, when Treasury notes replaced the circulation of gold sovereigns and gold half sovereigns. Legally, the gold specie standard was not abolished. The end of the gold standard was successfully effected by the Bank of England through appeals to patriotism urging citizens not to redeem paper money for gold specie. It was only in 1925, when Britain returned to the gold standard in conjunction with Australia and South Africa, that the gold specie standard was officially ended. The British Gold Standard Act 1925 both introduced the gold bullion standard and simultaneously repealed the gold specie standard. The new standard ended the circulation of gold specie coins. Instead, the law compelled the authorities to sell gold bullion on demand at a fixed price, but "only in the form of bars containing approximately four hundred ounces troy [12 kg] of fine gold". John Maynard Keynes, citing deflationary dangers, argued against resumption of the gold standard. By fixing the price at a level which restored the pre-war exchange rate of US$4.86 per pound sterling, as Chancellor of the Exchequer, Churchill is argued to have made an error that led to depression,