Louis Philibert Claude James Chappuis (born 10 November 1854 in Besançon; died 29 January 1934 in

Paris Paris () is the capital and most populous city of France, with an estimated population of 2,165,423 residents in 2019 in an area of more than 105 km² (41 sq mi), making it the 30th most densely populated city in the world in 2020. S ...

) was a French chemist and physicist.

Life

Chappuis was the son of philosophy teacher Charles Chappuis (1822–1897, lived from 1845 to 1869 in Besançon) and Louise Lydie Berthot (died 1909), a granddaughter of Nicolas Berthot, a mathematician in

Dijon Dijon (, , ) (dated) * it, Digione * la, Diviō or * lmo, Digion is the prefecture of the Côte-d'Or department and of the Bourgogne-Franche-Comté region in northeastern France. the commune had a population of 156,920. The earlies ...

. He attended schools in Besançon,

Caen Caen (, ; nrf, Kaem) is a commune in northwestern France. It is the prefecture of the department of Calvados. The city proper has 105,512 inhabitants (), while its functional urban area has 470,000,Grenoble. He enrolled in the

École normale supérieure École may refer to: * an elementary school in the French educational stages normally followed by secondary education establishments (collège and lycée) * École (river), a tributary of the Seine flowing in région Île-de-France * École, Savoi ...

(ENS) in Paris in 1874, then worked as a physics teacher at

Montauban Montauban (, ; oc, Montalban ) is a commune in the Tarn-et-Garonne department, region of Occitania, Southern France. It is the capital of the department and lies north of Toulouse. Montauban is the most populated town in Tarn-et-Garonne, an ...

in 1877, and at

Poitiers Poitiers (, , , ; Poitevin: ''Poetàe'') is a city on the River Clain in west-central France. It is a commune and the capital of the Vienne department and the historical centre of Poitou. In 2017 it had a population of 88,291. Its agglomerat ...

in 1878. He returned to Paris and was a Maître de conférences at the ENS from 1878 to 1882, passing the Agrégé in 1879. In 1881, he was appointed as Professor of Physics at the École centrale des arts et manufactures, and attained the doctoral degree in 1882 with a thesis on the

spectroscopy Spectroscopy is the field of study that measures and interprets the electromagnetic spectra that result from the interaction between electromagnetic radiation and matter as a function of the wavelength or frequency of the radiation. Matter wa ...

ozone Ozone (), or trioxygen, is an inorganic molecule with the chemical formula . It is a pale blue gas with a distinctively pungent smell. It is an allotrope of oxygen that is much less stable than the diatomic allotrope , breaking down in the lo ...

. He led the research laboratory of the ''Societé du Gaz de Paris''. Chappuis is interred in the family tomb in Chailly-sur-Armançon. He was uncle to his namesake James Chappuis'','' director of the automobile-maker

Citroën Citroën () is a French automobile brand. The "Automobiles Citroën" manufacturing company was founded in March 1919 by André Citroën. Citroën is owned by Stellantis since 2021 and previously was part of the PSA Group after Peugeot acquired ...

; the latter died in 1926 and is also interred at Chaily. He is not to be confused with the Swiss physicist Pierre Chappuis (1855–1916), also a professor of physics at the École Centrale.

Research

After the Swiss chemist

Jacques-Louis Soret Jacques-Louis Soret (30 June 1827 – 13 May 1890) was a Swiss chemist and spectroscopist. He studied both spectroscopy and electrolysis. He held the chairs of chemistry (1873-1887) and medical physics (1887-1890) at the University of Genev ...

discovered in 1863 that ozone is a three-atom molecule of

oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as wel ...

(O₃), numerous researchers detected ozone in the

atmosphere An atmosphere () is a layer of gas or layers of gases that envelop a planet, and is held in place by the gravity of the planetary body. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A s ...

through spectroscopy, among them Chappuis in 1880. Chappuis was the first known researcher to find that ozone was responsible for giving light that passes through it a bluish tint. He attributed this to absorption of yellow, orange, and red light by ozone. Ozone in the upper atmosphere, where pressure and temperature are low, is hence an important element for the blue color of the sky. This effect is known today as Chappuis absorption. In 1882,

Paul Hautefeuille Paul Gabriel Hautefeuille (2 December 1836 in Étampes – 8 December 1902 in Paris) was a French mineralogist and chemist. Biography From 1855 he studied at the École Centrale des Arts et Manufactures in Paris. Later on, by way of a recom ...

and Chappuis published the results of laboratory experiments showing that ozone could be purified and condensed to a deep blue liquid at temperatures under -112 degrees Celsius. Rayleigh scattering was already known in the 1880s, and was thought by contemporary scientists to be a sufficient explanation for the blue color of the sky. Chappuis's discovery was hence forgotten for a time. In 1952, the American geophysicist Edward Hulburt found that the blue color of the sky at sunset during the so-called blue hour could not be explained by Rayleigh scattering, and that the effect of Chappuis absorption by the

ozone layer The ozone layer or ozone shield is a region of Earth's stratosphere that absorbs most of the Sun's ultraviolet radiation. It contains a high concentration of ozone (O3) in relation to other parts of the atmosphere, although still small in rela ...

must be taken into account. The French meteorologist Jean Dubois proposed in 1951, that the

Earth's shadow Earth's shadow (or Earth shadow) is the shadow that Earth itself casts through its atmosphere and into outer space, toward the antisolar point. During the twilight period (both early dusk and late dawn), the shadow's visible fringe – sometimes ...

on the horizon could also be explained by Chappuis absorption, but this hypothesis was later disproven. Chappuis was one of the first users of Crookes tubes in 1896. The physician Jean François Moreau called Chappuis "one of the forgotten pioneers of clinical radiology". Chappuis had experimented in the 1890s with

X-ray An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30&nb ...

s for intrauterine photography.

Selected publications

* with Alphonse Berget: ''Leçons de physique générale,'' 3 volumes, Paris 1891–1892, 2. Auflage 1899–1911, 3rd edition 1923 * with Alphonse Berget: ''Cours de physique,'' Paris 1898 * with Alexis Jacquet: ''Éléments de physique industrielle,'' Paris, 3rd edition 1914, 11th edition 1949

References

{{Authority control 1934 deaths 1854 births French chemists 20th-century physicists 19th-century physicists 20th-century chemists 19th-century French chemists French physicists

Life

Research

Selected publications

Further reading

References