Cailletet, Louis Paul

(b. Châtillon–sur– Seine, Côte-d’Or, France, 21 September 1832; d. Paris, France, 5 January 1913),

physics, technology.

Cailletet, the son of a metallurgist, began his studies at the collége of his native city, completed them at the Lycée Henri IV in Paris, and then became a day student at the École des Mines. Upon his return to Châtillon he managed the forges and rolling mills of his father’s business, paying special attention to the operation of the blast furnaces; from this interest resulted his first series of investigations in metallurgy.

The permeability of metals to gases, notably that of iron to hydrogen, enabled Cailletet to explain some of the accidents that occurred in the tempering of incompletely forged pieces of iron, which, when retaining gas in dissolution, can be highly unstable in certain cases.

Some chemists, including J. J. Ebelmen, had concerned themselves with the analysis of gases from blast furnaces. However, they drew off the gases under conditions that produced gradual cooling, so that the dissociated elements were able to recombine. Cailletet undertook new investigations in which the gases were suddenly cooled at the very moment at which they were collected. The gases obtained under these conditions had a composition very different from that established by Ebelmen: little exhaust gas, little carbon dioxide, some hydrogen, some oxygen and carbon monoxide, and a large proportion of very finely divided carbon. The investigations of Henri Sainte-claire Deville on dissociation had given Cailletet the idea of correcting an experimental result invalidated by the very conditions of the experiment.

Cailletet is most famous for his investigations on the compression and liquefaction of gases. At the time there were still six gases that were considered permanent: oxygen, nitrogen, hydrogen, nitrogen dioxide, carbon monoxide, and acetylene. Liquefaction had not been achieved despite the use of what were considered enormous pressures. At the end of 1877 and the beginning of 1878 Cailletet liquefied all these gases shortly before Raoul Pictet, who employed a completely different procedure.

Cailletet had, following Andrews, recognized the importance of the critical temperature, above which liquefaction of a gas does not take place. In order to produce the necessary cooling, he had recourse to expansion, sometimes employing several expansions in a staged process. It was in this manner that he succeeded in liquefying oxygen by beginning with liquid ethylene and passing through the stage of liquid methane.

These results removed the last obstacle to a unified conception of the role of heat in changes in the physical state, thus realizing the prophetic views that opened Lavoisier’s Traité élémentaire de chimie. For these investigations Cailletet received the Prix Lacaze of the Académie des Sciences in 1883.

Other accomplishments of Cailletet include the installation of a 300-meter manometer on the Eiffel Tower; a study on the same structure of air resistance to the fall of bodies; the construction of devices, such as automatic cameras and air-sample collectors, for the study of the upper atmosphere by sounding balloons; and the study of a liquid-oxygen respiratory apparatus designed for high-altitude ascents. These investigations led to Cailletet’s being chosen president of the Aéro Club de France.

Cailletet was elected correspondant of the Académie des Sciences on 17 December 1877 and became académicien libre on 27 December 1884.

BIBLIOGRAPHY

I. Original Works. Cailletet presented all the reports of his investigations to the Académie des Sciences in the form of notes published in the Camptes rendus hebdomadaires des séances de l’Académie des sciences. See the following Tables générates des Comptes rendus… for vols, 32–61 (Paris, 1870), p. 86; for vols. 62–91 (Paris. 1888), p 99; for vols. 92–121 (Paris, 1900), pp. 106–107; for vols. 122– 151 (Paris. 1927), p. 114; and for vols. 152–181 (Paris, 1931), p. 124. His most important works are “Sur la condensation des gaz réputés incoercibles.” in Comptes rendus…,85 –1272: “De la condensation de l’oxygéne et de l’oxyde de carbone.” ibid. (24 Dec. 1877), 1213–1214, see also 1212. 1214–1219; “Sur la liqué factionde Pacétyléne.” ibid. (5 Nov. 1877). 851–852; “Liqué factiondu bioxyde d’azote.” ibid. (26 Nov. 1877), 1016–1017; “Recherches sur la liquéfaction des gaz,” in Annales de chimie, 5th ser., 15 (1878). 132–144, illustrated: “Surl’emploi des gaz liquéfiés et en particulier de l’éthyléne pour la production des basses températures.” in Comptesrendus… 94 (1 May 1882), 1224–1226; and “Nouvel appareil pour la liquéfaction des gaz. Emploi des gaz liquéfiés pour la production des basses températures.” in Annales de chimie, 5th ser.. 29 (1883). 153–164.

II. Secondary Literature. On Cailletet or his work, see Notices sur les travaux scientifiques de M. L. Cailletet (Paris, 1883), edited by Cailletet himself to support his candidacy for membership in the Academic des Sciences, and E. Colardeau, “Louis Cailletet,” in Nature (Paris), 41 , no. 1 (25 Jan. 1913), 143–144.

Jacques Payen