How Cleopatra Won Her Bet
Cleopatra and Marc Antony settled a wager more than 2,000 years ago. Now, a researcher believes she figured out how the Egyptian queen won the bet.
Tue Aug 3, 2010
Cleopatra and Marc Antony made a bet over whether the Egyptian queen could spend a small fortune on a single meal.
Cleopatra won the wager after drinking a cocktail made with a dissolved pearl.
Once assumed to be a legend, Cleopatra's concoction has been demonstrated to be possible.
Cleopatra, the last queen of Egypt, might have indeed drunk a pearl cocktail in a gulp, an experimental study has concluded.
Legend has it that, in order to show her wealth and power, Cleopatra VII (69 B.C. - 30 B.C.) made a bet with her lover -- the Roman leader Marc Antony -- that she could spend 10 million sesterces on one meal.
"She ordered the second course to be served. In accordance with previous instructions, the servants placed in front of her only a single vessel containing vinegar. ... She took one earring off, and dropped the pearl in the vinegar, and when it was wasted away, swallowed it," Roman naturalist and philosopher Pliny the Elder (23 - 79 A.D.) wrote in his Natural History.
Indeed, the pearl was not just any pearl. Pliny called it "the largest in the whole of history," a "remarkable and truly unique work of nature" worth 10 million sesterces.
Although the account was considered credible in antiquity, modern scholars have dismissed the story as fiction.
Giving ancient sources the benefit of the doubt, classicist Prudence Jones of Montclair State University in New Jersey experimented with vinegar and a five-carat pearl to find out whether the acetic acid concentration is sufficient to dissolve calcium carbonate.
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"All you need is vinegar and a pearl. In my experiments, I used a white vinegar sold in supermarkets. Wine vinegar was most common in the Greco-Roman world, so it is likely that's what Cleopatra used," Jones told Discovery News.
Jones found that a 5 percent solution of acetic acid, a concentration identical to that of white vinegar sold in supermarkets today, takes 24 to 36 hours to dissolve a pearl weighing approximately one gram. The process leaves a small amount of translucent, gel-like material on the surface.
"The calcium carbonate in a pearl reacts with the acetic acid in vinegar to produce calcium acetate, water and carbon dioxide," Jones wrote in the current issue of the Classical World journal, detailing her research.
The cocktail would have been less appetizing than a martini with the traditional olive, but still palatable.
"The calcium carbonate in the pearl neutralizes some of the acid, so the resulting drink is not as acidic as vinegar," said Jones.
The experiment also dispelled one of the most common misconceptions regarding Cleopatra's cocktail: the idea that only a super-concentrated vinegar could destroy a pearl.
"A higher concentration of acetic acid actually slows the reaction," said Jones.
Other experiments have shown that when both the pearl is crushed and the vinegar is boiled, the reaction takes less than 10 minutes.
"In Pliny's account, the time frame is compressed, as a large pearl would take more than 24 hours to react completely. But the outcome -- pearl destroyed, money spent and cocktail consumed -- is plausible," Jones concluded.
Adrienne Mayor, a research scholar at Stanford University's Departments of Classics and History of Science who specializes in investigating the basis of many ancient myths, folklore and popular beliefs, agrees.
"I think this research has convincingly demonstrated the technique that Cleopatra could have used to dissolve a pearl. We already know that this curious, intelligent queen carried out toxicological experiments," Mayor told Discovery News. "It's likely she softened the pearl in advance, then crushed it and placed it in a goblet to dazzle Marc Antony with her wealth and arcane scientific expertise."