Gustave-Adolphe Hirn

Gustave-Adolphe Hirn (21 August 1815 – 14 January 1890) was a French physicist, astronomer, mathematician, and engineer who made important measurements of the mechanical equivalent of heat and contributions to the early development of thermodynamics. He further applied his science in the practical development of steam engines. Life Hirn was born in Logelbach, near Colmar, into the prosperous textile-manufacturing family Haussmann. Baron Haussmann was a cousin. At 19, he entered his grandfather's cotton factory as a chemist. Later he worked as an engineer, and began research on mechanics, especially on calorics. Hirn carried out numerous experiments during his career, demonstrating the relevance of Carnot's principle in animated engines: the equivalence of thermal and mechanical energy. His work on thermodynamics is considered a major work of the 19th century. Indeed, he deduced from his work an equation of state that introduced both the notion of free volume and internal pressure, notions that would reappear with the work of van der Waals with a different corpuscular conception. He was made a member of the French Academy of Science in 1867; in 1880 founded a meteorological observatory near Colmar; and later devoted himself to astronomy. Hirn was educated in the shop, and his works are marked by much practical criticism of mere academic theory.