Jolly, Philipp Johann Gustav von

(b Mannheim, Germany, 26 September 1809; d. Munich, Germany, 24 December 1884)

physics.

Jolly became well-known as an experimental physicist primarily through his instruments and methods for making measurements. He was of Hugéenot descent and his father, an army captain who later became a merchant, was for many years the mayor of Mannheim. Jolly attended the Gymnasium in Mannheim and, from 1829 to 1834, the universities of Heidelberg and Vienna, where he also studied technology and mechanics, and then concentrated on mathematics and physics in Berlin. He received his doctorate in 1834 from Heidelberg and qualified there as privatdocent in mathematics, physics, and technology. In 1839 he became professor of mathematics, and in 1846 he obtained the chair of physics. At heidelberg, Jolly was often consulted by J. R. von Mayer, the discoverer of the law of the conservation of energy. At that time Jolly was concerned with questions of osmosis. Although his idea that the same amounts by weight of salt and water are exchanged through a membrane did not prove to be correct, he nevertheless contributed substantially to the elucidation of this process.

An outstanding experimenter, Jolly was also able to present the fundamentals of the physics of the period in a readily understandable manner in his Prinzipien der Mechanik (1852). In 1854 he was called to the University of Munich, where he was popular teacher until his retirement shortly before his death. In addition, Jolly was an expert consultant for the reorganization of Bavaria’s technical schools, a member of the Bavarian commission on standards, and German representative at the international conference on the meter held at Paris in 1872. He was also a member of the Bavarian Academy of Sciences and longtime chairman of the Munich Geographical Society.

With his mechanic A. Berberich, Jolly constructed and improved various measuring devices, including the spring balance, the air thermometer for determining the coefficients of expansion of gases (1874), the eudiometer, and the mercury air pump. In addition, he greatly increased the accuracy of balances. With the aid of his precision balances Jolly determined the earths’s gravitation (that is, the acceleration due to gravity) and density by means of a remarkable experimental procedure (1878-1881). Through measurements based on various methods he also succeeded in demonstrating the variability of the oxygen content of the air, which is important in meteorology. He found (1879) that the oxygen content of the “North Wind”—masses of polar air—is greater than that of the “South Wind”—masses of tropical air.

BIBLIOGRAPHY

I. Original Works. Bibliographies of Jolly’s works are in Böhm’s biography (see below); Poggendorff, I, 1199, and III, 695-696; and G. Hellmann, Repertorium der deutschen Meteorologie (Leipzig, 1883), pp. 221-222, meteorological papers only.

Among his writings are De Euleri meritis de functionibus circularibus (Heidelberg, 1834), the prize question of the University of Heidelberg for 1830; “Experimental-Untersuchungen über Endosmose,” in Annalen der Physik und Chemie, 78 (1849), 261-271; Die Principein der Mechanik gemeinfasslich dargestellt (Stuttgart, 1852); Ueber die Physik der Molecularkräfte (Munich, 1857); Das Leben Fraunhofers (Munich, 1866); “Ausdehnungs-Koefficienten einiger Gase und über Luftthermometer,” in Annalen der Physik und Chemie, jubilee vol. (1874), 82-101; “Die Anwendung der Waage auf Probleme der Gravitation,” ibid., n.s. 5 (1878), 112-134, and 14 (1881), 331-355, also in Abhandlungen der Bayerischen Akademie der Wissenschaften, math.-phys. Kl., 13 (1880), I, 3, 155-176, and 14 (1883), II, 1, 1-26; and “Die Veränderlichkeit in der Zusammensetzung der atmosphärischen Luft,” in Annalen der Physik und Chemie, n.s. 6 (1879), 520-544, also in Abhandlungen der Bayerischen Akademie der Wissenschaften, math.-phys. Kl., 13 (1880), II, 2, 49-79.

II. Secondary Literature. See G. Böhm, Philipp von Jolly, ein Lebens- und Charakterbild (Munich, 1886), with a bibliography of his works; and C. von Voit, “Philipp Johann Gustav von Jolly,” in Sitzungsberichte der Bayerischen Akademie der Wissenschaften zu München, math.- phys. Kl., 15 (1885), 118-136. Shorter biographies are “Jolly, Philipp von,” in Allgemeine deutsche Biographie, LV (1910), 807-810; and “Philipp Jolly,” in Badische Biographien, pt. 4 (Karlsruhe, 1891), 199-204.

Hans-GÜnther KÖrber