# John Tyndall John Tyndall was an Irish physicist who, in 1859, conducted the laboratory experiments that established the empirical basis of the [[Greenhouse Effect]]. Using a ratio spectrophotometer of his own design, he measured the capacity of gases to absorb and transmit infrared (radiant heat) and demonstrated that carbon dioxide, water vapor, and methane are powerful absorbers while the main atmospheric gases nitrogen and oxygen are nearly transparent to it. This identified exactly which gases trap outgoing heat and made the Radiative Forcing and Earth's Energy Balance of the atmosphere a measurable physical quantity rather than a speculation. His work, building on Joseph Fourier's earlier insight and preceding [[Svante Arrhenius]]'s calculations, is honored in the name of the UK's Tyndall Centre for Climate Change Research. (Eunice Newton Foote independently reported related findings in 1856.) *Stub — expand with the apparatus, the Foote priority question, and Tyndall's broader career in physics and glaciology.*