French magistrate and chemist. Published studies on phlogiston and crystallization. Liquefied ammonia gas. In collaboration with other famous chemists such as Antoine-Laurent Lavoisier (1743-1794) and Claude-Louis Berthollet (1748-1822), worked on the establishment of a chemical nomenclature. A fervent supporter of the Revolution, he held many public offices. Organized defense procurement and studied aerostatics. Director of the École Polytechnique and member of the Académie Royale des Sciences of Paris.