Biography

After this experience, Gay-Lussac was appointed tutor in chemistry at Ecole polytechnique in 1802. He began research on gas and vapour expansion and, in the same year, established the thermal coefficient law or “equal expansion of gases and vapours”.Along with Biot, he carried out two balloon ascents, exceeding 7000 m (holding a 40 altitude record), to study the Earth’s magnetic field.

The result of his research was presented to the Academy of Sciences in 1804:in particular, he showed that taken in volumes, oxygen and hydrogen combine to form water in a proportion of 100 oxygen for 200 hydrogen (law of combining volumes or Gay-Lussac’s law).He established laws on “the combination of gaseous substances” which are the foundation of atomic theory.Working in particular with his collaborator and friend Louis-Jacques Thénard, he conducted extensive research on substances such as potassium, sodium, potash, sulphur, boron production, iodine compounds, hyposulphuric acid, silicon, chlorine.

He also presented very advanced research on Prussian blue, cyanogen and cyanhydric acid, and developed a number of measuring instruments.However, Gay Lussac was not only a chemist of the highest order, he was also a remarkable physicist.He held simultaneously the chairs of physics at the Sorbonne and general chemistry at the Museum of Natural History.

In 1816, he invented the portable siphon barometer, then in 1817 the chlorometer and the alkalimeter.A process for analysing silver money was adopted by the Parish Mint in 1823.

He became MP for his native town, Saint-Léonard de Noblat (Haute-Vienne) and, like his master Berthollet, was awarded the rank of Peer of France.

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