Yes, Kahn did footnote the Monroe cypher information,
attirubitng it to Edmund C. Burnett, in his "Letters of
Members of the Continental Congress."
I've also received two other citations for more on Monroe's
cypher from the mail list Intelligence Forum, a quite informative
source on crypto and intelligence matters, many of whose
members are active or former members of a variety of intel
agencies, as well as scholars of the field. http://www.intelforum.org
>From Hayden Peake:
The Monroe Cypher (aka: WEO28) is discussed (who used it
and when, etc.) in WEBER's book, United States Diplomatic
Codes and Ciphers 1775-1938, (Chicago: Precedent Publishing,
1979). The code itself is reproduced in an appendix (pp. 478-489).
If a copy of the book is not to hand, let me know and I can fax the
code itself.
WEBER can be contacted at: [EMAIL PROTECTED], tel: 414-785-1910.
-----
And from Louis Kruh:
A more detailed version (30 pages and 108 footnotes) of Ralph
Weber's interesting article, "America's First Encrypted Cable" is
included in his "Masked Dispatches: Cryptograms and Cryptology
in American History, 1775-1900." Published by Center for
Cryptologic History, NSA, 1993, 236 pp.