Johann Philipp Gustav von Jolly (26 September 1809 – 24 December 1884) was a German experimental physicist. He measured gravitational acceleration with precision weights and also worked on osmosis. He also designed several tools like the Jolly balance in 1864, a special eudiometer in 1878, as well as his own air pump and Jolly air thermometer.
Born in Mannheim, as the son of merchant and Marie Eleonore Jolly, who came originally from France.
His primary education was in Mannheim. Jolly attended joined Heidelberg University in 1829, to study physics and mathematics. During his studies he worked in Vienna as a mechanician for factories and mining plants, before returning back to Heidelberg in 1834, where he received his PhD. After his studies, he was appointed professor of mathematics in 1839 and professor of physics in 1846, in Heidelberg.
He moved to the University of Munich in 1854, where he took the position once held by Georg Simon Ohm. He was knighted in 1854 (and henceforth referred to as von Jolly).
Jolly died in Munich.
Von Jolly was initially skeptical of Julius von Mayer's theory on the mechanical equivalent of heat. Ernst Mach recalls an anecdote where von Mayer when looking for Jolly for advice, but Jolly contested: "then water should be warmed by merely shaking it." Von Meyer immediately left the room without saying a word, and after a few weeks, he surprised von Jolly in his office by shouting "and so it is!" .[1] [2]
One of Jolly's students at the University of Munich was Max Planck, whom he advised in 1878 not to go into theoretical physics.[3] Nevertheless, Planck's later work lead to the discovery of quantum mechanics. Later in life Planck reported:[4]