You’ve likely heard the name Antoine Lavoisier—the discoverer of oxygen’s true nature, the father of chemistry—but do you know about the woman behind the curtain, the scientific genius who is Marie-Anne?
It’s 1771 in France, and 13-year-old Marie-Anne Paulze has just received a marriage proposal from the wealthy, 50-year-old Count of Amerval. Marie-Anne forcefully objected to the arrangement, calling the count an unfeeling fool, an ogre. But her father, Jacques, couldn’t just tell the count to buzz off -- he might lose his job as a senior member of the Ferme Générale, a taxation organization.
What he could do was find another way to prevent the union. Still, it wasn’t exactly what you’d call a solution. Jacques asked one of his colleagues, Antoine Lavoisier, to marry his daughter instead. He was *only* 28. This was a good deal for Antoine. The money Marie-Anne brought with her meant he could finally build the chemistry lab of his dreams.
While Marie-Anne finished growing up, she filled her days with scholarly pursuits. She studied English and Latin, learned chemistry from Antoine’s colleagues Jean Baptiste Michel Bucquet and Philippe Gingembre, and even practiced art under celebrated painter Jacques-Louis David.
Before long, Marie-Anne became a lab colleague in her own right. She took down scientific data, edited their reports, and documented their research procedures in writing and sketches that included enough detail for other scientists to recreate them. This reproducibility endowed their work with a certain validity.
Significantly, she also translated English chemistry texts by the leading thinkers of the day. along the way making note of her own ideas on the topics and highlighting all of the errors the original author made. This meant Antoine was kept up to date on emerging theories in his field. In order to refute prevailing ideas, you have to know about them first. Marie-Anne’s work allowed the dynamic science duo to blow up everything the world held dear about chemistry, then rebuild the discipline from the ground up.
In the late 18th century, chemistry was still deeply entangled in alchemy. The dominant theory was phlogiston, developed by Georg Ernst Stahl (1659–1734). Phlogiston, Greek for inflammable, was a fiery element involved in combustion. To explain the changes he observed while burning substances, Stahl declared that combustible materials were made up of ash and phlogiston. After burning, all that remained was the “dephlogisticated” ash.
“This is in fact the reverse of what happens during combustion when oxygen combines with a combustible material,” Dr. John B. West wrote in the American Journal of Physiology in 2013.
Once Marie-Anne translated Irish chemist Richard Kirwan's Essay on Phlogiston and the Constitution of Acids—pointing out all of the chemistry mistakes Kirwan made— Antoine could write out a rebuttal. Their rejection of phlogiston laid the groundwork for their discovery of the true nature of oxygen.
Antoine’s 1789 publication Elementary Treatise on Chemistry offered a unified, unparalleled new view of chemistry. By weighing the reactants, then weighing what remained after a reaction, Antoine could describe the law of conservation of mass in chemical reactions. To make accurate measurements, they had to create new equipment. The essay included a list of elements and a system for chemical nomenclature. The text also contained thirteen of Marie-Anne’s exquisite engravings depicting all of the apparatuses they invented.
As the threat of the French revolution rumbled like a thundercloud on the horizon, Marie-Anne’s hands moved furiously to sketch their experiments on oxygen. Chemistry would never be the same.
“Lavoisier was the first person to clearly state the role of oxygen, carbon dioxide, and nitrogen in respiration,” Dr. West explained. “Priestley is often credited with ‘discovering’ oxygen just as Columbus ‘discovered’ America but neither Priestley nor Columbus correctly identified what they found.”
In some cases, Marie-Anne's drawings are the only record of their experiments. Dr. West theorizes that Antoine was too busy with his tax collecting work to ensure written accounts of the experiments were created.
Kirwan and Antoine debated the issue of phlogiston for several years before Kirwan finally conceded. And he wasn’t even Antoine’s biggest scientific nemesis. Antoine had the misfortune of enraging a scientist named Jean-Paul Marat who excelled at holding grudges. Antoine had publicly declared that Marat’s theories of mesmerism were poppycock, pseudoscience. When Marat applied to the Académie des Sciences, Antoine ensured he was rejected.
Utterly humiliated, Marat took advantage of the French Revolution to exact his deadly revenge. He used Antoine’s work with Marie-Anne’s father as a tax collector to get him convicted of tax fraud. The punishment? Off with his head. And while they’re at it, off with Marie-Anne’s father’s head, too. Though she spent 65 days in prison, Marie-Anne managed to escape the episode bankrupt, but alive.
All of their lab equipment and scientific notebooks were seized. But Marie-Anne remained dedicated to preserving her husband’s legacy.
Antoine had a whole series of memoirs planned. At least one volume, Mémoire sur la chaleur (Memoir on heat), named Marie-Anne as coauthor. Marie-Anne took umbrage with one of Antoine’s young colleagues being chosen to write the introduction to the Mémoires. She should be the one to pen them.
Unfortunately, she took this opportunity to call out all of the people she believed were to blame for her husband’s premature demise. Her husband’s colleagues objected, so she was left with a large number of unbound manuscript copies. No publisher would touch his memoir, so she printed and distributed Mémoires de Chimie herself, without her introduction.
The government returned some of the lab equipment and notes to Marie-Anne, and eventually exonerated Antoine. Too little, too late.
Marie began running a weekly scientific salon. Among the luminaries she hosted were Benjamin Franklin, naturalist Alexander von Humboldt, astronomer Pierre-Simon Laplace, mathematicians Gaspard Monge and Joseph-Louis Lagrange, physicist Siméon Denis Poisson, and physicist Benjamin Thompson aka Count de Rumford.
Rumford was an American who had opposed the American Revolution, even spying and recruiting for the British. When he was outed, a mob came after him. He swiftly left for England, abandoning his wife. By the time he met Marie-Anne, his wife had died. Rumford was entirely bewitched by Marie-Anne’s intellect, writing that she was “one of the cleverest women ever known and uncommonly well-informed.”
Marie-Anne agreed to marry him, but refused to give up her first husband’s last name. It was not a long, nor happy union. She was accustomed to being treated like a scientific equal in the lab, but Rumford didn’t allow her inside his lab. She was to play no role in his discoveries in thermodynamics. This was just the beginning of their chafing desires.
Marie-Anne declared the count “would make me very happy if he would but keep quiet.” He often referred to her as “the dragon.”
She was also accustomed to a much more lively social life. Rumford enjoyed solitude. The final straw came when she threw a party herself. He instructed the guards not to allow the guests in the gate. To get him back, she dumped boiling water over all of his flowers in the garden. They separated after four years of marriage.
As the mother of chemistry who spent her life playing with fire, perhaps she was a dragon.
“Marie Anne Paulze Lavoisier: The Mother of Modern Chemistry,” by Cassandra T. Eagle and Jennifer Sloan, The Chemical Educator, October 1998.
“Celebrating Madame Lavoisier,” by Rupert Cole, Science Museum of Britain, January 20, 2020.
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