Clocks and Timekeeping in Lavoisier’s Experiments on Animal Respiration. The Chemical Revolution, Its Material Culture and Taken-for-Granted Knowledge

Around 1777/78, the French nobleman and chemist Antoine Lavoisier (1743–1794) started reflecting on the mechanism of animal respiration and transpiration. The results of long years of experimentation, carried forward with the help of his collaborator Armand Séguin, were only published after 1790. The two premiers mémoires, published in the annual collection of the Académie des sciences of 1789 (out in 1793) and 1790 (out in 1797), and the two seconds mémoires, published in the Annales de chimie in 1814 but presented at the Académie in 1791 and 1792, are decisive steps towards an interpretation in modern chemical terms of these biological processes. As for the study of respiration, Lavoisier puts into question Joseph Priestley’s theory according to which “the respiration of animals has the property of phlogisticating air” – whereby Priestley means that, in the course of respiration, oxygen (dephlogisticated air) is turned into nitrogen (phlogisticated air). Lavoisier overturns this hypothesis, first by establishing a parallel between respiration and combustion. Observing that not all the inspired oxygen is turned into carbon dioxide, Lavoisier posits that all animal bodies must already contain carbon and hydrogen. Respiration, therefore, is the process by which oxygen combines