TY - MANSCPT DB - Science History Institute DP - Science History Institute M2 - Courtesy of Science History Institute. Rights: Public Domain Mark 1.0 TI - First Day Cover commemorating the 75th anniversary of the American Chemical Society ID - w9505056r CY - United States DA - 1951/// YR - 1951 AV - Witco Stamp Collection, Box 5 VL - Witco Stamp Collection, Box 5 AN - Witco Stamp Collection, Box 5 UR - https://digital.sciencehistory.org/works/w9505056r AB - Cachet depicts two chemists working in a laboratory. KW - Postage stamps KW - Chemists KW - Postmarks KW - American Chemical Society KW - Science on postage stamps KW - Cachets (Philately) KW - First day covers (Philately) LA - English ER -