Get Nrdly Free Trial Built with Nrdly

Spy Techniques: A Housewife’s Primer

How to be a Spy!

Good housewives, rejoice! It turns out your skills could get you hired by an intelligence agency. Or at least they could have in the eighteenth century. Read the Good Housewife’s Primer for Effective Spies to find out how.

Sending intelligence without being discovered was—and still is—of crucial importance. In the eighteenth century, this was because postal offices typically had a black chamber operation—a concerted effort to open, read, copy, and re-seal letters sent by foreign diplomats.

You could, of course, have written in code—substituting numbers or other words for sensitive words. The members of George Washington’s Culper Ring used such a code:

A 658 225 hath made a most generous 436. He shall 442 both 223 and 219s from the 178 for our 589 in 727.

723 begs 711 will send him more of the tonic. It is much needed here.

I made that message up on the fly. I’ll let you look up the numbers in the Code Book yourself. It’s available here: The Culper Code Book.

But as you can see the problem with that message is that anyone who intercepts it knows there’s a code to be broken. It would likely take some time to decipher, but a traitor who managed to steal a copy of the code could very easily read it. If the letter had been written by anyone within the Culper Ring, their identity would be revealed and their role immediately compromised.

Ciphers—substituting each letter in a word with another letter in a systematic fashion—can be broken as well, and certainly don’t do anything to conceal the fact that a clandestine communication is being carried on.

A better way would be to camouflage the message so well that no one would suspect it was even there. Invisible ink was commonly used, and any good housewife would have had the necessary items in her pantry. Lemon juice, onion juice, and milk can all be used to write an invisible message that is revealed by holding the paper up to candle light. These substances compromise the fibers in the paper, and this is what enables the message to be inscribed on the sheet of paper.

A prisoner with nothing else on hand might even use his urine.

But the most intriguing type of invisible ink, according to Nadine Akkerman’s research, was formed from artichoke juice. Susan Hyde, a Stuart sympathizer, writing to her brother Edward Hyde advises him to “let mee know your minde” by way of artichokes. A reference, Akkerman surmises, to invisible ink.

Crushing the leaves to get the juice was quite the production, but any good housewife would have been able to extract it. And in this age of Youtube, it isn’t hard to find precise instructions on the extraction of the juice. I’ll be sharing one such in the Resources section below this post.

Invisible ink, however, is quite easily revealed. Anyone who thought to hold a letter up to light would be able to see the secret writing concealed within the penned lines of a letter.

Imagine that my letter above had been written in invisible ink and sent to Major Benjamin Tallmadge, the man responsible for recruiting the members of the Culper Ring. Anyone who intercepted the letter would have been a fool not to examine it thoroughly.

Washington’s spies used a better kind of invisible ink—one that needed a chemical reagent to reveal it—so their correspondence was safe.

But women devised even better ways to pass on their messages. During the American Revolutionary War, a woman whose house was commandeered by British soldiers found the most ingenious way of getting the information she overheard to George Washington.

She’d write down everything she heard on tiny slips of paper. Then she’d tightly fold up the paper, place it on top of a metal button, cover it with cloth and sew it onto her young son’s coat. The boy would be sent off to see his older brother, who would detach the buttons from his coat and retrieve his mother’s messages. These were then transcribed and sent on to Washington.

Another woman, Anna Smith Strong, used her laundry to signal in which cove a member of the Culper Ring could dock his boat. The color of her laundry and the way in which the garments were hung out to dry conveyed very specific messages to the longshoreman making his way across the Sound.

The story about Anna Strong comes from Brian Kilmeade’s brilliant George Washington’s Secret Six, a compelling account of the Culper Ring and its efforts.

But there was an even easier way to send a message—a basket of eggs. This is from Nadine Akkerman’s research as well, and the Youtube video on how it’s done simply must be watched.

All you need is a few eggs, some vinegar, and some cold water, and of course small pieces of paper on which to write your message. The eggs are soaked in vinegar to soften the shells. When the shells have sufficiently softened, you can cut a slit into them and insert your message into the egg. Then the eggs are soaked in cold water so the shells may re-harden.

After that, all you have to do is walk your basket over to whoever it is you’re sending your messages to. Who would suspect something quite so innocuous as a basket of eggs?


1) Artichoke Juice as Invisible Ink: https://www.youtube.com/watch?v=-Rmj0kvsCZU

2) Secret Messages in Eggs: https://www.youtube.com/watch?v=u5AOqOxFDiA

If you’d like to know more, please preorder Prussian Counterpoint. You’ll get it at the discounted price of $3.99 and you’ll get, among other things, a FREE ebook, Rehearsal Notes, in which I share some of what I learned on the subject of espionage while researching this novel.

espionage, Haydn mysteries, Prussian Counterpoint, Rehearsal Notes, spy techniques

  1. Intriguing blog post. Gave me inspiration :-). Your Joseph Haydn series looks very interesting. I’m a Flemish novelist. My novel about Charles Baudelaire was translated and published in English in 2014. “Baudelaire’s Revenge” has been published in English, French, and Russian.

  2. Nupur says:

    Glad you enjoyed it, Bob! Your book sounds fascinating!

Leave a Reply