Gustave-Adolphe Hirn (1815–90)

French engineer and physicist. Chemist (colorist) in his father’s cotton-spinning factory near Colmar, 1834. When the dye works was closed in 1842, moved to engineering and worked on improving the plant machinery. In 1848, published on the laws of friction and studied the effectiveness of different lubricants. In 1857, made an important contribution to thermodynamics with a work on the mechanical equivalent of heat. From 1880, concentrated on astronomy; installed an observatory in his house. Corresponding member, Académie des sciences, 1867.