It is early August in the year 1794, and jails, choked with the enemies of Maximilien Robespierre and his Committee for Public Safety, are emptying their human contents onto the streets of Paris in the aftermath of his downfall and execution in late July. Among those released is a woman, once the sparkling center of Parisian scientific life, now widowed at the hand of Citizen Guillotine and utterly destitute.
She has been many things in her life - a gifted painter who studied under Jacques-Louis David, a translator and editor of international scientific texts, the head of a regular Monday salon that attracted the capital's greatest scientific and economic minds, and a leading light in the fight for the replacement of phlogiston theory with a set of ideas that will become the basis of modern chemistry. Lacking for nothing and universally adored at her height, she is now, at the moment of her release from jail after sixty-five days of anxiously waiting to be dragged before the dread revolutionary Tribunal, unsure from whence the basic necessities of life are to come.
But Madame Lavoisier, born Marie-Anne Pierrette Paulze (1758-1836), is nothing if not a fighter, and this diminution in her fortunes she will survive, as she always has. She was born in 1758 to a father whose connections gave him a position in the General Farm, monarchical France's privatized tax collection system, and a mother who passed away when she was only three years old. After the loss of her mother, her father kept his boys with him but sent young Marie-Anne off to a convent where several of her aunts happened to be installed. For the next ten years, this was where she lived and, as these sorts of stories go, her experience was not as bad as it might have been. She had family at the convent to watch after and care for her, and the education offered was a rich one, embracing math, drawing, handwriting, music, history, geography, and regular recreational periods. At the end of her time at the convent, she was a confident, talented girl, sure of herself and her abilities.
Her father, who came to pick her up after she had turned thirteen in order to have her run his household, had not seen Marie-Anne since depositing her at the convent a decade ago, and was unfathomably surprised at the fact that the crying child he had dropped off was now a self-assured girl. Her time as her father's domestic organizer was short-lived, however. The arrival of a new girl, a daughter of a rich member of the Farm General, was so much blood in the water to the Parisian social climber set, and soon after settling down, her father's patron put pressure on him to marry her off to an elderly acquaintance of low means and unknown character. To his credit, her father resisted the demand, but realized that it would be only the first of many to come, not all of which he would be able to fend off. The only thing to do, it seemed, was to marry her away, quickly, to somebody who was at least a decent human being, preferably of independent fortune, and not too horrendously old.
He found his man in the form of one of the General Farm's most honest and hard-working individuals, a man unique in the system for his concern with fairness and the scientifically driven improvement of France's agricultural and manufacturing capacities, Antoine-Laurent de Lavoisier. He was 28 with a growing reputation as France's most innovative and rigorous chemical investigator. She was 13 and was already known as an intelligent and engaging social hostess. In the France of that era, that was all a husband expected of his wife, and all a wife expected of herself, but the Lavoisiers were not a typical couple. Though she loved the intellectual give and take of her famous Monday salons, frequented by the era's greatest scientists and political thinkers, she was not content to sit on the sidelines while her husband carried on his researches and investigations.
Marie-Anne asked Antoine-Laurent to teach her what he knew of chemistry and physics and he responded with the first instinct of all great teachers: How can I teach a subject I know so little of? Irresponsible teachers who haven't really investigated their topic tend to believe they know it completely, and are willing and eager to show off their knowledge at any time, but the great ones know that, beneath the apparent certainty of the textbook, there is a teeming mass of assumptions and uncertainty, and so they teach only fearfully, out of reverence for the messiness of actual truth, and Antoine-Laurent was one such. Marie-Anne persisted, however, and sooner than any might have guessed, she was acting the triple role of scientific secretary, publicist, and translator in one of the late 18th century's greatest scientific battles.
This conflict revolved essentially around two competing theories about how to explain fire. The phlogiston theory, popular in Britain, held that materials possess in different degrees a substance called phlogiston which, during combustion, escapes from that material, and gets absorbed by air. Under this model, a substance stops burning either when it has used up all of its phlogiston, or when the air gets saturated in it and can hold no more. Lavoisier, however, taking as his starting point not the general wisdom of his chemical colleagues but rather the principle of the Conservation of Matter, believed that combustion was the result of a gas in the air combining with the atoms of a flammable material to produce a reaction that generated flame and new gases. Not only the (ultimately correct) attack on phlogiston, but the claim that atmospheric air was made up of a combination of different gases, and the insistence on using conservation of mass as a starting point for chemical research, generated a rift that pitted the Old Chemistry against the New, and in the service of the New Chemistry Marie-Anne kept up a steady correspondence, beseeching those on the fence to come down on the side of the anti-phlogiston theory, and began translating and commenting on British pro-phlogiston tracks, culminating in her 1788 annotated translation of Richard Kirwan's 1787 Essay on Phlogiston and the Constitution of Acids.
When not translating or keeping up her large scientific correspondence, she sat in on Antoine-Laurent's experiments, recorded the relevant data, and used her skills (honed in study with France's pre-eminent painter of the era, Jacques-Louis David) as an artist to capture the layout of his experimental apparatus for future ages. She even went on inspection tours of French industry and wrote reports suggesting areas of improvement, in the spirit of Antoine-Laurent's role in the General Farm as a manufacturing analyst. Together, they bought a country estate and sank both money and time into introducing agricultural reform among the farmers there, with varying degrees of success. Marie-Anne was Antoine-Laurent's trusted intellectual companion, his immediate link with scientific work in English and Latin that he could not himself understand, and the staunchest defender of his theories.
Her identity as a woman in the more biological sense, however, he was seemingly less interested in. Always busy, and by all accounts far more exhilarated by scientific theory than carnal pleasures, he did not bring particular fire to the bed chambers, and after some years Marie-Anne undertook an affair with Pierre Samuel Du Pont, which Antoine-Laurent most likely knew about but didn't seem to mind in the grand tradition of Voltaire's permissive relations with the mathematician and physicist Émilie du Châtelet. As a side note, Marie-Anne played an indirect but crucial role in the shaping of the United States as a result of her relationship with Du Pont. During the French Revolution, Du Pont fled to America, where he expressed the opinion that the Louisiana Territory, recently gained from Spain, ought to be sold to the United States. He was fully intending to stay in the US until Marie-Anne begged and prodded him to return during the Napoleonic Era, where he was elevated to a position of power and became a leading voice on a crucial three-man committee recommending to Napoleon that he sell the Louisiana Territory. Napoleon, for his part, listened to Du Pont's ideas and reasons, agreed, and the United States doubled in size.
Returning to the story.
Everything seemed to be going well for Marie-Anne on the eve of the French Revolution. Wealthy, admired, influential, intellectually and romantically stimulated, she and her husband straddled the political line between the reformers and the old order, seeking to fundamentally reshape the governance of France without totally destroying the basic fabric of the nation. Lavoisier repeatedly served on committees representing the interests of the Third Estate and argued strenuously for changes in the economic system of France, but as a member of the General Farm he was also associated with the hated Old Regime's tax collection system, and when the Revolution’s Committee of Public Safety decided the entire Farm must be indicted as treasonous and counter-revolutionary, Lavoisier was lumped in with his far less scrupulous colleagues.
His reputation as a reformer and genuinely conscientious government officer, however, nearly saved him. A friend of the Lavoisiers, Jean Baptiste Pluvinet, was related to the wife of the deputy reporter preparing the cases against the Farm General, a monsieur Dupin. Dupin extended an offer to Marie-Anne to try Lavoisier separately from the rest of the Farmers, thereby almost assuredly guaranteeing him a better hearing. She responded in a fit of almost inexplicable outrage, saying that it would dishonor Antoine-Laurent to be tried separately from his colleagues, that he was clearly innocent, and that Dupin should be ashamed to even suggest the idea. Dupin, taken aback by the sudden rejection of his offer, left, and the proposal was never put forward again. Antoine-Laurent de Lavoisier was convicted and executed by guillotine on May 8, 1794, and on June 14, Marie-Anne herself was arrested and fully expected to share the same fate. We'll never know why she rejected the opportunity held out by Dupin to potentially save the life of her husband. Lavoisier scholar Jean-Pierre Poirier holds it likely that she simply misread the gravity of the situation Antoine-Laurent was in. Believing him to be so clearly innocent that any jury would and must acquit him, she apparently didn't realize until it was too late the true nature of justice under Robespierre, and it cost Antoine-Laurent his life, and she her freedom for 65 days until the fall of Robespierre allowed her to walk free again.
The months following her release were hard-fought as she marshaled her remaining friends and fellow widows to demand redress from the French government for the seizure of her property and assets. Slowly, most of what was once hers was returned to her, including her father's priceless library and her husband's treasured laboratory equipment. Her finances re-established, she took her place again as the leading light of Paris's scientific salon scene, hosting such mathematical and scientific luminaries as Laplace, Lagrange, Poisson, Monge, Humboldt, and the man who was to become, to both of their detriments, her second husband: the Count de Rumford.
There is much to say about Rumford and Marie-Anne's relationship, but before she allowed herself to give way to his entreaties, she embarked on what was to be her final public service to the chemical world, when she undertook to publish the collected works of Lavoisier that he had been working on during his imprisonment. The Memoires de Chimie was published in 1803 and featured in two volumes many of the papers that Lavoisier, and Lavoisier's supporters, had delivered before the French Academy in the heady days of modern chemistry's infancy. She agonized over the introduction, outlining Antoine-Laurent's place in history and lamenting his sudden end, but left the main text largely as it was when Lavoisier and his assistant Seguin were first compiling it. That duty completed, Marie-Anne felt herself free at last to accept the marriage proposal of the Count de Rumford.
Rumford was a fascinating individual (he was one of my favorites to use as a spy/scientist operative character in my Frederick the Great webcomic back in the day), part soldier, part spy, part revolutionary materials scientist, it would be a full century and a half until researchers picked up his investigations into the physical, thermal, and chemical properties of food and clothing to advance our scientific knowledge of the stuff of everyday existence (see in particular the work of Ellen Swallow in the early 20th century). He didn't drink, hardly ate, and all he wanted from life was quiet in which to do his research. He was, however, fascinated by the widow Lavoisier, a woman so conversant with so many aspects of emerging science, who knew everyone worth knowing in the scientific community, and who also happened to be ludicrously wealthy.
He allowed himself to ignore the fact that she lived to make her home the social center of a free-wheeling set of intellectual lights. She allowed herself to ignore his repeated wistful comments about the joys of quiet and solitary research. Mutually convinced they could recover the magic partnership that Antoine-Laurent and Marie-Anne shared, they married in 1805, and almost instantly regretted the act. Rumford hated the constant entertaining, and Marie-Anne hated having to constantly refuse hospitality to her circle of friends and admirers. They made each other miserable, and when the separation came at last in 1809, it was a blessing to all concerned.
For the next quarter century, Marie-Anne enjoyed life to its fullest measure. Though not directly venturing again into the scientific arena, she provided a crucial location where French scientists and mathematicians could meet international figures who were passing through Paris, and informally discuss new, emerging ideas. She had survived the French Revolution, the Terror, the rise of Bonaparte, the fall of Bonaparte, and the 1830 Revolution, coming out on top of every change of fortune by virtue of her tenacity and innate sense of self-worth, and the affection of her large circle of friends who had been drawn to her by her intellect, generosity, and refreshingly brusque candor. As a thirteen year old, newly married and fresh from the seclusion of the convent, she had by force of will made herself into a major component of the development and publicizing of a revolutionary new approach to chemistry, and she ended her days as the undisputed leader of the French scientific social scene. While she had not always lived happily, there are none who can say that Marie-Anne Paulze Lavoisier had not lived.
FURTHER READING:
The source for all things Lavoisier is Jean-Pierre Poirier, whose biography of Antoine-Laurent is widely regarded as the standard work on the subject, and who also wrote a companion volume devoted just to Marie-Anne, La Science et l'Amour: Madame Lavoisier (2004). It does have what feels like a tendency to go into longer accounts of people and events only partially connected to Marie-Anne by way of padding out the story, but what is there, from extensively quoted letters to crucial data about the intellectual and political events that shaped Marie-Anne's time, is your best chance of learning about this remarkable 18th century figure. As far as I know, however, it isn't available in English translation, so if you don't know French then I'd point you to a chapter on Madame Lavoisier in the recently published Women in their Element (2019).