Milton Friedman wrote in "Monetary History of the United States" that the money was more stable when interest rates were set by the blind workings of supply & demand than when the Fed did it, and backed it up with charts and statistics.
"As is clear to the naked eye in Chart 1, the stock of money shows larger fluctuations after 1914 than before 1914 and this is true even if the large wartime increases in the stock of money are excluded. The blind, undesigned, and quasi-automatic working of the gold Standard turned out to produce a greater measure of predictability and regularity—perhaps because its discipline was impersonal and inescapable—than did deliberate and conscious control exercised within institutional arrangements intended to promote monetary stability."
Chart 1 is on page 4 and plots the x axis 1867 to 1960 and the y axis plots deposits and currency, and yeah, it's pretty clear to the naked eye.