While poking around Google Books, I stumbled on the following two references that might be of interest to this list. The first is cited by Kahn.
\emph{The Military Telegraph During the Civil War in the United States: With an Exposition of Ancient and Modern Means of Communication, and of the Federal and Confederate Cipher Systems ; Also a Running Account of the War Between the States} By William Rattle Plum Published by Jansen, McClurg & Company, 1882 http://books.google.com/books?id=trpBAAAAIAAJ "Secret Writing" The Century Published by The Century Co., 1913 http://books.google.com/books?id=LbIul9mwYtsC&printsec=titlepage#PPA83,M1 --Steve Bellovin, http://www.cs.columbia.edu/~smb --------------------------------------------------------------------- The Cryptography Mailing List Unsubscribe by sending "unsubscribe cryptography" to majord...@metzdowd.com