Born July 21, 1810, in Aachen; died Jan. 19, 1878, in Paris. French physicist and chemist. Member of the Paris Academy of Sciences (1840).
After graduating in 1832 from the Ecole Polytechnique in Paris, Regnault continued his studies at the Ecole des Mines. He became a professor of chemistry at the Ecole Polytechnique in Paris in 1840 and a professor of physics at the Collège de France in 1841. In 1847 he was appointed chief engineer of mines, and in 1854, director of the Sèvres porcelain factory.
In 1835, Regnault began his study of organic compounds. In 1840, together with J. B. A. Dumas, he developed the chemical theory of types. Regnault conducted exacting experiments to determine the physical constants (specific heat, coefficient of expansion, heat of vaporization, vapor pressure) of gases, vapors, liquids, and solids. He also measured the speed of sound in gases and proved that the coefficient of thermal expansion varies for different gases. He conducted experimental tests of Dulong and Petit’s law and the Boyle-Mariotte law. He carried out the most accurate determination for his time of the mechanical equivalent of heat, and he also compiled tables of vapor pressure. Regnault designed an air thermometer, pyrometer, and hygrometer and worked on the improvement of gas lighting in Paris.
WORKSCours élémentaire de chimie, 6th ed., vols. 1–4. Paris, 1870.
Premiers éléments de chimie, 6th ed. Paris, 1873.