Johann Philipp Gustav von Jolly (26 September 1809 – 24 December 1884) was a German physicist and mathematician.

Born in Mannheim as the son of merchant Louis Jolly and Marie Eleonore Jolly, he studied science in Heidelberg, Vienna and Berlin. After his studies, he was appointed professor of mathematics in Heidelberg in 1839 and physics in 1846. He moved to Munich in 1854, where he took the position once held by Georg Simon Ohm.^[1] In 1854, he was knighted (and henceforth referred to as von Jolly).

Jolly was, first and foremost, an experimental physicist. He measured gravitational acceleration with precision weights and also worked on osmosis.

One of his students at the University of Munich was Max Planck, whom he advised in 1878 not to go into physics,^[2] saying, "in this field, almost everything is already discovered, and all that remains is to fill a few unimportant holes." Planck replied that he did not wish to discover new things, only to understand the known fundamentals of the field. Nevertheless, Planck's work opened the quantum mechanics field.

Jolly died in Munich.

Selected works

• Anleitung zur Differential- und Integralrechnung, 1846 – Manual of differential and integral calculus.
• Die Principien der Mechanik, 1852 – The principles of mechanics.
• Eine Federwage zu exacten Wägungen, 1864 – A spring balance for exact weight measurements.
• Die Anwendung der Waage auf Probleme der Gravitation, 1878, zweite Abhandlung, 1881 – Application of a scale to problems of gravitation in two parts.