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If we think about chemical experiments, we envision people wearing laboratory smocks and safety glasses and busy with pipettes and test tubes. So it is hard to imagine that this drawing represents a chemical laboratory. Yet the picture shown here was part of an extensive series of experiments on human breathing carried out by the chemist Antoine Laurent de Lavoisier (1743\u20131794) in the early 1790s with his younger colleague Armand-Jean Fran\u00e7ois Seguin (1767\u20131835) in Paris. According to protocols, Seguin often served as the test person and can be identified here as the \u201cman in the barrel\u201d. The two persons facing each other are Lavoisier and his wife Marie.[i]<\/a> Antoine Lavoisier had already made a name for himself by determining the role of the then newly discovered element oxygen in the process of combustion. In the course of precise and systematic measurements he also proved that the mass of materials in chemical reactions remains constant. He formulated the latter finding, known to this day as the law of conservation of mass, in 1789 in his main work Trait\u00e9 \u00e9l\u00e9mentaire de la chimie<\/em>. With the system of nomenclature of chemical elements which he also described in his Trait\u00e9<\/em>, Antoine Lavoisier is considered the founder of modern chemistry.<\/p>\n\n\n\n Marie-Anne Pierrette Paulze Lavoisier was the unofficial \u201cmanager\u201d of the laboratory. As was normally the case with well-to-do women in the 18th<\/sup> century, access to education and science was opened primarily through experimenting in a home environment. After marrying Antoine Lavoisier \u2013 she was only 13 years old at the time \u2013 she was introduced to the work in the laboratory and learned English and Latin in order to be able to translate scientific treatises for her husband. His laboratory books are pervaded with her handwriting and detailed, true-to-scale sketches of experimental setups and instruments. In this way she contributed to the formulation, dissemination, and thus empirical verifiability of the experiments \u2013 a quality criterion that marks scientific works to this day.[ii]<\/a><\/p>\n\n\n\n <\/p>\n\n\n\n The drawings from the 1790s shown here are ascribed to Marie Lavoisier. They attest to her artistic training but served in particular to illustrate her husband\u2019s essays on respiration that were later published together under the title M\u00e9moires de physique et chimie<\/em>. However, the death of the chemist by guillotine in the turmoil of the Reign of Terror in 1794 and the subsequent conflict between Marie Lavoisier and Armand Seguin about copyright claims prevented an official publication of the book. In 1805, Marie finally circulated the work without acknowledgement of Seguin\u2019s participation and without illustrations, which would have disclosed his cooperation.[iii]<\/a> An exact description of the illustrations has therefore not come down to us and the precise process of the experiments remains obscure. The aim of the chemists \u2013 as far as can be deduced from other sources \u2013 was to develop a theory that would explain the process of respiration in a biological context. To this end they tried, among other things, to quantify the intake of oxygen and the emission of carbon dioxide during breathing. In the experiment, the latter occurred by direct exhalation into a bowl with a lime solution. The reaction of the solution with carbon dioxide produced calcium oxide, or lime, which could then be weighed. Seguin himself was weighed before and after every experiment in order to determine the amount of hydrogen that was depleted through breathing.[iv]<\/a> Antoine Lavoisier and Seguin also determined that during breathing, physical exertion had an influence on the amount of hydrogen consumed and in the end on the combustion of nutrition, thus leading to questions in the field of biochemical metabolism.[v]<\/a><\/p>\n\n\n\n When the Lavoisiers were not working in the laboratory, they hosted a salon in which experiments and instruments were demonstrated and current theories discussed. The report of a guest from the year 1787 suggests that Marie Lavoisier was perceived as a \u201cscientific lady\u201d.[vi]<\/a> Alongside tea and coffee, which were served in the salon, \u201cher conversation on Mr. Kirwan\u2019s Essay on Phlogiston, which she is translating from the English, and on other subjects, which a woman of understanding, that works with her husband in his laboratory, knows how to adorn, was the best repast.\u201d[vii]<\/a> From various references like this one we get an idea of the scientific work of women in the 18th<\/sup> century. Since the publications of Antoine Lavoisier do not mention the participation of his wife, her drawings take on a special importance. In them her contribution is documented for posterity.<\/p>\n\n\n\n After the death of her husband, Marie Lavoisier continued to organise the discussion and experiment evenings and managed the generous instrument collection, which is now preserved in the Mus\u00e9e des Arts et M\u00e9tiers in Paris. One of the precision scales that was used in Lavoisier\u2019s laboratory between 1768 and 1789 can be seen until 6 April 2025 in the exhibition \u201cWhat is Enlightenment? Questions for the 18th<\/sup> Century\u201d<\/a> in the Deutsches Historisches Museum.<\/p>\n\n\n\n <\/p>\n\n\n\n [i]<\/a> Cf. Marco Beretta, Imaging the Experiments on Respiration and Transpiration of Lavoisier and Seguin. Two Unknown Drawings by Madame Lavoisier, <\/em>in: Nuncius 27 (2012), pp. 163\u2013191, here: p. 188.<\/p>\n\n\n\n [ii]<\/a> The reproducibility of experiments had practical limits: only a few science enthusiasts had the financial means to buy the expensive instruments. Antoine Lavoisier could only afford to carry out his experiments due to his work as royal tax collector.<\/p>\n\n\n\n [iii]<\/a> Cf. Beretta,p. 191.<\/p>\n\n\n\n [iv]<\/a> Cf. Ibid., p. 188.<\/p>\n\n\n\n [v]<\/a> Vgl. Philipp Ball, Experimente. Die Chemie der Atmung, online article from 03.07.2024, URL: https:\/\/www.haupt.ch\/magazin\/natur\/experimente\/?srsltid=AfmBOoqTG-8N0ynOYmdiCEDIizO_ImAkWAhy87vV5IbiskxJhBH-0ZSd<\/a>, Access: 11.11.2024.<\/p>\n\n\n\n![\"\"](\"\/blog\/wp-content\/uploads\/2024\/12\/2-1.jpg\")
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