Spy Blog from the International Spy Museum

SPY’s Book Specialist, Matt Arnold

SPY Artifact: Handkerchief with Secret Writing

Invisible ink.  Lemon juice, milk, and, for those most desperate, urine are the most commonly known recipes for invisible ink.   These techniques were literally child’s play for many of us.  Yet, when Mata Hari was arrested with a vial of a German issued invisible ink, it was used as evidence of her status as a German spy.   But what use can these potions and methods practiced for centuries still hold for our national security?

Well, quite a bit according to the CIA.  The oldest classified documents in US archives happen to be German invisible ink recipes from 1917 and 1918. As recent as 2002, the CIA successfully defended the classification in federal court fearing the “risk of compromise of…intelligence methods” and of allowing the “more sophisticated methods of secret writing” to fall in terrorists hands.  Perhaps we have Mata Hari to thank for those recipes?

Although the CIA is still protecting the German’s secret recipes, we have our own rich tradition.  George Washington himself was an avid practitioner and dabbler in invisible inks.  Washington instructed the use of “sympathetic stain” developed by Jon Jay’s brother for the transmission of secret information.

In Invisible Ink by John Nagy, we are introduced to the American Revolution as this war of deception waged by British and American forces employing invisible inks, codes, secret rendezvouses, spy rings, and complicated military deception operations.  After their defeat England’s chief of intelligence was reputed to have said, “Washington did not really outfight the British, he simply outspied us!”  I guess tea makes a poor invisible ink…

Dr. Thomas Boghardt, Historian

The world of intelligence is populated by intriguing, amazing, and occasionally outright bizarre characters. One of my favorites remains Margaretha Geertruida Zelle, aka Mata Hari. She fascinates me not so much because of her espionage career, but because her image has so powerfully shaped our perception of women in espionage.

Born in 1876 in the Netherlands, Margaretha Zelle spent several years in Dutch Indonesia as the wife of a Dutch colonial officer. After falling out with her husband, she returned to Europe, adopted the stage name “Mata Hari,” and launched a sensational career as an exotic dancer. Promiscuous, flirtatious, and openly flaunting her body, she captivated her audience (mostly men) virtually overnight.

During World War I, Mata Hari apparently got involved with German intelligence, using her female wiles to worm secrets out of high ranking Allied military officers. While the details of her brief espionage career remain murky, in 1917 French counter-intelligence intercepted an enemy telegram implicating her as a German spy. The French arrested, court-martialed, and executed her by firing squad in 1917.

Mata Hari had long been a master of deception. For example, she successfully spread the notion that she was a Javanese princess, performing an ancient sacred dance of her homeland. In reality, she was plain Dutch, but her claim conferred an aura of authenticity on her autodidactic dance performances. As the war ended, the myth created by herself exploded. Rumors purported that she had refused to be blindfolded and blown a kiss to her executioners. More fiction than fact, the 1931 movie Mata Hari, starring Greta Garbo, fully turned her into an icon.

Today, female spies are often referred to as “Mata Haris.” In reality, such allusions usually miss the point—the real Mata Hari was not much of a spy, and of course not every female (or male) spy uses seduction to gather intelligence. But I can’t help suspect that Mata Hari herself would be delighted to have become the symbol of the female spy as seductress. Despite her premature death, she may have the final laugh after all. 

Nothing is what it seems