Joseph Louis Gay-Lussac

Joseph Louis Gay-Lussac (UKɡeɪˈluːsæk, USˌgeɪləˈsæk, ʒɔzɛf lwi ɡɛlysak; 6 December 1778 – 9 May 1850) was a French chemist and physicist. He is known mostly for his discovery that water is made of two parts hydrogen and one part oxygen (with Alexander von Humboldt), for two laws related to gases, and for his work on alcohol–water mixtures, which led to the degrees Gay-Lussac used to measure alcoholic beverages in many countries. Gay-Lussac was born at Saint-Léonard-de-Noblat in the present-day department of Haute-Vienne. The father of Joseph Louis Gay, Anthony Gay, son of a doctor, was a lawyer and prosecutor and worked as a judge in Noblat Bridge. Father of two sons and three daughters, he owned much of the Lussac village and usually added the name of this hamlet of the Haute-Vienne to his name, following a custom of the Ancien Régime. Towards the year 1803, father and son finally adopted the name Gay-Lussac. During the Revolution, under the Law of Suspects, his father, former king's attorney, was imprisoned in Saint Léonard from 1793 to 1794. He received his early education at the hands of the Catholic Abbey of Bourdeix, though later in life became an atheist. In the care of the Abbot of Dumonteil he began his education in Paris, finally entering the École Polytechnique in 1798. Three years later, Gay-Lussac transferred to the École des Ponts et Chaussées, and shortly afterward was assigned to C. L. Berthollet as his assistant. In 1804 he was appointed répétiteur (demonstrator) to Antoine François Fourcroy at the École Polytechnique, whom he succeeded in 1809 as professor of chemistry. From 1809 to 1832, he was also the professor of physics at the Sorbonne, a post which he only resigned for the chair of chemistry at the Jardin des Plantes. In 1821, he was elected a foreign member of the Royal Swedish Academy of Sciences. In 1831 he was elected to represent Haute-Vienne in the chamber of deputies, and in 1839 he entered the chamber of peers. He was elected a Foreign Honorary Member of the American Academy of Arts and Sciences in 1832.