Many people recognize the name Antoine-Laurent Lavoisier (A. Lavoisier) (1743-1794). He was a well-known French chemist, who discovered the role oxygen plays in combustion and gave the element its name. He even holds the nickname the “father of modern chemistry,” as his thorough experiments led to a shift from chymistry to what we know associate with chemistry today. However, not many people know about the contributions of Marie-Anne Paulze-Lavoisier, A. Lavoisier’s wife.
Paulze-Lavoisier was a key member of her husband’s research group and contributed without any credit. She never signed their papers, but she was central to much of their success.
Paulze-Lavoisier learned chemistry from two of A. Lavoisier’s collaborators, Jean-Baptiste Michel Bucquet (1746-1780) and Philippe-Joachim Gengembre (1764-1838). Bucquet was a French chemist, physician, and teacher, as well as a member of the French Royal Academy of Sciences. He worked with A. Lavoisier on a total of 26 memoirs that were published at the Academy of Sciences. Gengembre was also a French chemist, but he was also an inventor who discovered phosphate (PH3). Thus, Paulze-Lavoisier had access to a chemical education of a very high standard, which allowed her to examine chemical questions of the time alongside her husband.
One such relevant theory was the phlogiston theory, which was developed by George Ernst Stahl in the early decades of the 18th century. The phlogiston theory stated that phlogiston was a substance that was contained in any combustible body. It was supposed to be released during combustion, accounting for the loss of mass that typically occurred. However, there was conflicting evidence from the calcination of metal. Metal was heavier after calcination, which refuted the idea that it lost its phlogiston. So, there was much debate over the validity of the phlogiston theory.
In the 1770s, A. Lavoisier determined that air diminished during the calcination of metal and that the increase in weight of the calcinated metal was in accordance with this decreased weight of the air. This led him to realize that during combustion, a part of the surrounding air was combined with the burning material, thus disproving the phlogiston theory.
So, A. Lavoisier began to publicly attack the phlogiston theory, instead proposing his theory that combustion was a reaction of a metal and a part of air that supported respiration. And this was where Paulze-Lavoisier truly shined. The Lavoisiers and their research group translated and refuted two pamphlets by Irish phlogistician Richard Kirwan (1733-1812). Despite not seeking or attaining any recognition, Paulze-Lavoisier was the key leader behind these pamphlets. The first pamphlet, Essai sur le phlogistique, combined translation with counter-attacks. Following each translated section, there was a rebuttal based on the Lavoisiers’ ideas. Indeed, Swiss naturalist Horace Bénédict de Saussure (1740-1799) was dissuaded from believing the phlogiston theory in favor of A. Lavoisier’s oxygen theory because of the pamphlets. Paulze-Lavoisier was central to publicly disproving the phlogiston theory. And this shift from the phlogiston theory to the oxygen theory is typically viewed as a key moment in the creation of modern chemistry.