John Tyndall was a British physicist who produced early, seminal advances in the physics of energy flows in the Earth’s atmosphere. In his investigation of the radiant heat and the acoustic properties of the atmosphere, he built the first ratio spectrophotometer that he used to measure the absorptive powers of gases such as water vapor, carbonic acid (carbon dioxide), ozone and hydrocarbons. He identified the large differences in the abilities of "…perfectly colourless and invisible gases and vapours…” to absorb and transmit radiant heat. He noted that oxygen, nitrogen and hydrogen are almost transparent to radiant heat, whilst other gases are quite opaque. He correctly concluded that among the constituents of the atmosphere, water vapor is the strongest absorber of radiant heat and is therefore the most important gas controlling the Earth's surface air temperature. He said that without water vapor the Earth's surface would be "held fast in the iron grip of frost." He later speculated how changes in water vapor and carbon dioxide could be related to climate change. Tyndall also showed that ozone was an oxygen cluster rather than a hydrogen compound and made significant studies in Alpine glacier-related studies.

Sources

• Cleveland, Cutler (Lead Author); Peter Saundry (Topic Editor). 2008. "Tyndall, John." In: Encyclopedia of Earth. Eds. Cutler J. Cleveland (Washington, D.C.: Environmental Information Coalition, National Council for Science and the Environment). [First published in the Encyclopedia of Earth December 2, 2006; Last revised August 26, 2008; Retrieved May 22, 2009]. 
• Wikipedia Contributors, John Tyndall, Wikipedia The Free Encyclopedia, Accessed 22 May 2009.