oseph Louis Gay-Lussac (French: [ʒɔzɛf lwi ɡɛlysak]; also Louis Joseph Gay-Lussac; 6 December 1778 – 9 May 1850) was a French chemist and physicist. He is known mostly 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.

Biography

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, on behalf of 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. Later, in the care of the Abbot of Dumonteil he began his education in Paris, finally entering the École Polytechnique in 1798. Gay-Lussac narrowly avoided conscription and by the time of entry to the École Polytechnique his father had been arrested (due to Robespierre's Reign of Terror). Three years later, Gay-Lussac transferred to the École des Ponts et Chaussées, and shortly afterwards was assigned to C. L. Berthollet as his assistant. In 1802, he was appointed demonstrator to A. F. Fourcroy at the École Polytechnique, where in (1809) he became professor of chemistry. From 1808 to 1832, he was 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.

Gay-Lussac married Geneviève-Marie-Joseph Rojot in 1809. He had first met her when she worked as a linen draper's shop assistant and was studying a chemistry textbook under the counter. He fathered five children, of whom the eldest (Jules) became assistant to Justus Liebig in Giessen. Some publications by Jules are mistaken as his father's today since they share the same first initial (J. Gay-Lussac).

He was an atheist.

Gay-Lussac died in Paris, and his grave is there at Père Lachaise Cemetery. Some of Gay-Lussac's descendants live in Brazil, South America (de Salusse Lussac/Lussac Do Coutto/Do Coutto Monni) and in Ontario,Canada. From the Coutts branch, the roots of the family can be retraced to the Highland Scottish clan Farquharson of Invercauld.[citation needed]

Achievements

Gay-Lussac and Biot ascend in a hot air balloon, 1804. Illustration from the late 19th century.

• 1802 – Gay-Lussac first formulated the law, Gay-Lussac's Law, stating that if the mass and pressure of a gas are held constant then gas volume increases linearly as the temperature rises. This is sometimes written as V = k T, where k is a constant dependent on the type, mass, and pressure of the gas and T is temperature on an absolute scale (in terms of the ideal gas law, k = n·R/P).
• 1804 – He and Jean-Baptiste Biot made a hot-air balloon ascent to a height of 7,016 metres (23,018 ft) in an early investigation of the Earth's atmosphere. He wanted to collect samples of the air at different heights to record differences in temperature and moisture.
• 1805 – Together with his friend and scientific collaborator Alexander von Humboldt, he discovered that the composition of the atmosphere does not change with decreasing pressure (increasing altitude). They also discovered that water is formed by two parts of hydrogen and one part of oxygen (by volume).
• 1808 – He was the co-discoverer of boron.
• 1810 – In collaboration with Louis Thenard, he developed a method for quantitative elemental analysis by measuring the CO2 and O2 evolved by reaction with potassium chlorate.
• 1811 – He recognized iodine as a new element, described its properties, and suggested the name iode.
• 1824 – He developed an improved version of the burette that included a side arm, and coined the terms "pipette" and "burette" in an 1824 paper about the standardization of indigo solutions.
• In Paris, a street and a hotel near the Sorbonne are named after him as are a square and a street in his birthplace, Saint-Léonard-de-Noblat.

Academic lineage

Gravesite of Gay-Lussac Academic genealogy Notable teachers Notable students

• C. L. Berthollet (1748–1822), Paris
• Antoine François, comte de Fourcroy (1755–1809), Paris

• Jean-Jacques Colin (1784–1865), répétiteur in 1809–1817
• Pierre Robiquet (1780–1840), répétiteur in 1813–1818
• César Despretz (1791–1863), répétiteur in 1817–?
• Jules Pelouze (1807–1867), répétiteur in 1831–1837?
• Edmond Frémy (1814–1894)
• Henri-Victor Regnault (1810–1878)
• Justus Liebig (1803–1873)

Publications

• Chemistry courses of the École Polytechnique, Vol.1&2
• Lessons of Physics, Faculty of Sciences in Paris, (November 6, 1827, March 18, 1828)