Spies and Codes

I just finished the very enjoyable mystery, Secrets of a Lady, by Tracy Grant. The hero and heroine are both former spies who served on opposite sides in the Peninsular War.

The story reminded me of yet another topic from the Romance Writers of America National Conference last month–Spies and Codes.

Author Patricia Coleman‘s workshop at The Beau Monde mini-conference focused on spies and codes of revolutionary France and Georgian England.

Chappe’s Semaphore Code

Claude Chappe

As in midwifery, France seems to have been more advanced than England in sending messages using codes. Claude Chappe and his brothers devised a way of communicating across long stretches of revolutionary France using a series of towers within viewing distance of each other. Napoleon later expanded this system, sending messages as far as Venice.

The Chappe Towers used a system of movable arms to represent letters and numbers. To see a Chappe Tower at work, check out this BBC video. I can’t think of a way to put one of these into a story (yet) but the use–or misuse–of a Chappe Tower made it into fiction as a plot point in Alexandre Dumas’ Count of Monte Cristo. 

Chappe’s system used a very specialized series of symbols like these, crude but effective, at least until the invention of the telegraph.

Codes vs. Ciphers

Patricia also covered a bit about Napoleon’s Grand Chiffre, or Great Cipher. Strictly speaking, codes and ciphers are not the same thing, though the words are often used interchangeably by people like me! Here’s a lengthy discussion of the differences, but I would say, a code is definitely weaker than a cipher. Napoleon’s Grand Chiffre was indeed very complex. In his book The Man Who Broke Napoleon’s Codes, Mark Urban discusses this cipher and the breaking of it in great detail. I touched a bit upon it in my blog post, Five Facts about the Peninsular War.

Patricia also gave us this handy-dandy decoder wheel, rather like something we would have found in a serial box as kids! Codes could also use a book as a key, much like the codes used by General Washington’s spies.

Coded messages will show up in two stories I have in revisions right now, so this class was very timely.

Now, if I can only send a character to France and work part of the story around those semaphore towers!

Have you read any good historicals incorporating codes and ciphers? Please share!

Images: Book cover, Amazon; Chappe and Chappe Tower, Wikimedia; semaphore code and code wheel, the author