John Tyndall (1820-1893) is one of Ireland's greatest scientists and educators. Amongst his many achievements, he is best known for the explanation of why the sky is blue - the scattering of light by small particles suspended in the atmosphere. This colour is described as Tyndall Blue. He was also a gifted public lecturer, an avid promoter of the public understanding of science, and a famous mountaineer. Beside that Tyndall was one of the first scientists to recognise the earth's natural greenhouse effect and to identify the relative radiative forcing values of the different greenhouse gases. In 1853 he was appointed Professor of Natural Philosophy at the Royal Institution in London and began to work beside Michael Faraday. He succeeded Faraday as Superintendent in 1862.