ictured is the first XB-block note that I have been able to document from the Bureau of Engraving and Printing revealed the existence of the paper experiment carried out in the XB, YB and ZB blocks of the $1 Series of 1935A silver certificates: specifically, X00000001B-X00720000B—control 75 percent linen cuttings and 25 percent cotton cuttings, Y00000001B-Y00720000B—50 percent linen cuttings and 50 percent cotton cuttings, and Z00000001B-Z00576000B—50 percent linen cuttings and 50 percent raw cotton fiber. Those serial number ranges were printed early, out-of-sequence, in 1940. The remaining serials in the XB, YB and ZB blocks were printed in 1942. Moffitt, who has been searching for these experimentals, saw the January 2022 Reader’s Showcase report of a note from the ZB block so submitted the photo of these two discoveries. The full data for the notes illustrated here are: X00225235B A1999/1456 and Z00371979B I2138/1670.
