The first cryptarithm ever published? 

    ETSNPO
   x  LRAM
   ALMTNSR
  PPSMNLT
 LEAAPPM
PSRPNES  _
APASLERTER


American Agriculturalist, Volume 23, December 1864, p. 349.

The cryptarithm shown above appeared in a puzzle column in Orange Judd's magazine American Agriculturalist, entitled "No. 109 Mathematical Puzzle".  It is a ideal keyed multiplication (one word, 1-0); the keyword is a proper name.  No constructor is credited, and it does not appear to have been a particularly popular puzzle: I have not found any further examples scanning through a couple more years' worth of the magazine (thanks to the Internet Archive for providing a digital copy of the 1864 volume).

This article is copyright 2014 by Michael Keller.  All rights reserved.