Regnault, Henri Victor

[renyoh] (1810–78) French physical chemist: made experimental contributions to study of thermal properties of gases.

Regnault’s father was an officer in Napoleon’s army and died in 1812 in the Russian campaign; the boy was soon orphaned, but a friend of his father found him a job in a Paris shop. He worked hard for entrance to the École Polytechnique, graduated and became first assistant and then his successor there in 1810. From 1854 he was director of the famous Sèvres porcelain factory, until his laboratory was destroyed by the Prussians in the war of 1870. Regnault had no clear plan of research, but he did valuable work in several areas. He discovered a series of organo-chlorine compounds, including the chlorinated ethenes and CCl4 . He worked on specific heat capacities and measured deviations from and Petit’s Law; he measured the thermal expansion coefficient of gases accurately and found it varied slightly with the nature of the gas; and he studied the deviations from Law. He was cautious and no theorist, but his careful measurements made over 30 years were used by physical chemists and engineers for a generation.