Nicolas Lémery (Rouen 1645 - Paris 1715) was an important French chemist and physician, author of several treatises. After completing his studies as an apprentice pharmacist, he acquired a pharmacy in Paris but had to leave due to religious intolerance towards the Protestant community, of which he was a part. After taking refuge in England, he returned to Paris in 1686 and, converted to Catholicism, resumed both his work in the pharmacy and his chemistry lessons. Convinced that chemistry must be a science demonstrable, he affirmed the need to use pragmatic-experimental procedures, contributing considerably to the spread of the emerging discipline. Of particular value were his skills as a teacher and popularizer. His brilliant lessons were characterized by a clear and understandable language devoid of those obscure arguments of the alchemical-Paracelsian vision and attracted scholars, bourgeois, nobles, obtaining great success. Its admission in 1699 to the Académie Royale des Sciences in Paris formalized the importance of chemistry as a single and specific discipline in France.