Series Is Presented Here As Two Variables--(1)--Seasonally Adjusted Data, 1867-1906 (2)--Seasonally Adjusted, 1907-1946 (3)--Original Data, 1947-1968 (4)--Seasonally Adjusted, 1947-1968. Data Represent Vault Cash Of All Banks Subtracted From Currency In Circulation Outside The Treasury And Federal Reserve Banks. Data Are For The Wednesday Nearest The End Of The Month. Source: Friedman And Schwartz, Monetary Statistics Of The United States (NBER, 1970), Table 27, Column 3, Pp. 402-415.
This NBER data series m14125a appears on the NBER website in Chapter 14 at http://www.nber.org/databases/macrohistory/contents/chapter14.html.
NBER Indicator: m14125a
Release: NBER Macrohistory Database
National Bureau of Economic Research, Currency Held By The Public for United States [M1425AUSM144SNBR], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/M1425AUSM144SNBR/, August 3, 2015.