Jolly, PHILIPP JOHANN GUSTAV VON, German physicist, b. at Mannheim, September 26, 1809; d. at Munich, December 24, 1884. His family came originally from France at the end of the seventeenth century. After attending the gymnasium and lyceum at Mannheim, Jolly went to the University of Heidelberg in 1829, where he studied chiefly mathematics and physics. From 1832 to 1833 he was at Vienna, taking up the technological branches, working as a mechanician, and visiting factories and mining plants. Returning to Heidelberg in 1834, he took the degree of Doctor of Philosophy and began his career as a teacher of mathematics, physics, and technology. He became extraordinary professor of mathematics in 1839, and ordinary professor of physics in 1846. In 1854 he was called to the University of Munich to succeed Ohm as professor of physics. His principal work was in experimental physics, for which he devised numerous new apparatus, and modified and improved the older forms. His studies of osmosis, of the problems of gravitation, of the density of the earth, of the composition of the air, etc., suggested the design of the Jolly balance (1864), of a special eudiometer (1879), of an improved mercury air-pump, of the Jolly air thermometer. The following are some of his published works: “De Euleri merito de functionibus circularibus” (prize essay, Heidelberg, 1834); “Anleitung zur Differential- und Integralrechnung” (Heidelberg, 1846); “Die Prinzipien der Mechanik” (Stuttgart, 1852); “Physik der Molecularkrafte” (Munich, 1857). He contributed to Poggendorff’s “Annalen”, “Heidelberger Jahrbiicher”, and “Berichte der Miinchener Akademie der Wissenschaften”.