Claude Pouillet

Content sourced from Wikipedia, licensed under CC BY-SA 3.0.

Claude Servais Mathias Pouillet (16 February 1790 – 14 June 1868) was a French physicist and professor at the Sorbonne. He studied at the École normale supérieure and worked at the Conservatoire national des arts et métiers from 1829 to 1849, first as a professor and later as an administrator. After Pierre Louis Dulong’s death in 1838, Pouillet took the physics chair at the Faculty of Sciences, and he briefly held the chair at the École Polytechnique in 1831. He was forced to retire in 1852 when he refused to swear an oath to the new imperial government.

The Pouillet effect, named after him, describes the heat produced when wetting dry sand, published in 1822. He also built a pyrheliometer and, around 1837–1838, made the first quantitative measurements of the solar constant, estimating it at 1228 W/m²—very close to the modern value of about 1367 W/m². He once used the Dulong-Petit law to estimate the Sun’s surface temperature, obtaining about 1800 °C; this was corrected in 1879 by Josef Stefan to 5430 °C.

Pouillet wrote on optics, electricity, magnetism, meteorology, photography and photometry. In optics he studied diffraction, and in electricity he designed sine and tangent galvanometers. He helped develop a real mathematical treatment of the greenhouse effect, refining Fourier’s work on Earth’s surface temperature and suggesting that water vapor and carbon dioxide trap infrared radiation to warm the planet. His widely used textbook Éléments de physique expérimentale et de météorologie was published in four parts and was translated into German as Lehrbuch der Physik und Meteorologie. Svante Arrhenius cited Pouillet’s work extensively in 1896.