Data Are Values Of A Fine Ounce At The Average Quotation. The Prices Are The Average Of Bar Silver In London, Per Ounce British Standard (.925 Fine), In Equivalent United States Gold Coin, Of An Ounce 1.000 Fine, Taken At The Average Price And Par Of Exchange. The London Price Is Given In Depreciated Currency After September 21, 1931. The United States Was Off The Gold Standard On And After April 19, 1933. Figure For 1933 Is For The 1932-33 Fiscal Year. Source: Annual Report Of The Directors Of The Mint, 1933, Pp.86-87.
This NBER data series a04018 appears on the NBER website in Chapter 4 at http://www.nber.org/databases/macrohistory/contents/chapter04.html.
NBER Indicator: a04018
Release: NBER Macrohistory Database
National Bureau of Economic Research, Price of Bar Silver for London, Great Britain [A04018GB00LONA286NNBR], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/A04018GB00LONA286NNBR/, September 1, 2015.