Regnault
Achievements: Provided data that was used in the development of the theory of thermodynamics
Born: July 21, 1810; Aix-la-Chapelle, France
Died: January 19, 1878; Paris, France (Aged 68)
Field & Discipline: Science; Physics; Physicist
Language: French
Education: Ecole Polytechnique, Paris
Life & Times:
Regnault was the son of an army officer who died in the Russian campaign of 1812. His mother died soon afterwards and a friend of his father’s oversaw Regnault’s education, after which was he took employment in a draper’s shop in Paris. Regnault managed to scrape up the money for coaching for the entrance examination to Ecole Polytechnique and as admitted in 1830. He completed his studies at the Ecole des Mines and then travelled in Europe studying mining techniques and metallurgical technology. He studied under [taught by] Liebig* at Giessen, and under [taught by] Boussingault* at Lyon. In 1836 he became research assistant to [assistant to] Gay-Lussac* at the Ecole Polytechnique.
Regnault made notable contributions to organic chemistry at this time, particularly concerning the action of chlorine on ethers, and the research which led to his discovery of vinyl chloride, dichloroethylene, trichlorethylene and carbon tetrachloride. By 1839, he had performed experiments on the specific heats of isomers which attracted the attention of [attracted attention of] JBA Dumas*, who had been conducting experiments into vapour density as part of his research into the atomic theory. Dumas persuaded Regnault to undertake further experimental research into the specific heats of solids and liquids. As a result of his successes, Regnault was elected to the chemical section of the French Academy of Sciences in 1840 and in the same year succeeded Gay-Lussac as professor of chemistry at the Polytechnique.
In 1841 he was appointed professor of physics at the College de France where he taught optics to [taught] Fizeau*. The following year Regnault was tasked by the government with the task of recalculating all the physical constants involved in the design and operation of steam engines. Reliable data on, for example, vapor pressure and temperature, was essential in setting up safety measures for steam engines. This project resulted in the researches on the thermal properties of gas for which Regnault is remembered. His exactitude and rigor supplied the experimental evidence for theories about the atomic composition of gases advanced earlier by chemists such as the Italian [proved theories of] Avogardo*. Regnault recalculated the specific heats of numerous solids, liquids and gases, and worked out improved values for atomic weights based on measurements of specific heat.
He developed apparatus that produced unprecedentedly precise measurements. With his air thermometer, he was able to determine the absolute expansion of mercury and he also devised a hgyrometer. While working on the compressibility of gases and investigating deviations from Boyle’s law, Regnault discovered that all gases have slightly different coefficients of expansion, and demonstrated that the expansion coefficient of gases varied according to the nature of the gas and its initial pressure. He proved that Boyle’s law of the elasticity of an ideal gas is only approximately true for real gases. He also definitely disproved the belief that the specific heat of a gas decreased as it was compressed.
Regnault’s work was recognized with the award of the Legion of Honor, and the Rumford and Copley medals of the Royal Society, and it drew students from all over Europe, among them William Thomson, later [knew] Kelvin*, who met Regnault in 1845 and worked in Regnault’s laboratory. In 1854, Regnault was appointed director of the Sevres porcelain factory. During the Franco-Prussian war of 1870/71 all his instruments and books were destroyed, and his son, who was a painter, was killed.
Extra Connections: His work related to that of [work related to] Klatte*
Assessment: Regnault produced a valuable data of work on the properties of gases which was used by physicists after him, notably in the field of heat theory.
Oneliner: HV Regnault, 19th-century French physicist
Bibliography:
- Fox, Robert, The Caloric Theory of Gases, From Lavoisier to Regnault, Clarendon Press, Oxford, 1971.