This aqueous vapour [1 minute, video]

John Tyndall was the first scientist to prove that Earth’s atmosphere has a greenhouse effect. [Wikipedia]

Tyndall’s experiments showed that molecules of water vapour, carbon dioxide, and ozone are the best absorbers of heat radiation. He concluded that water vapour is the most important gas controlling Earth’s surface temperature. [NASA Earth Observatory]

This eloquent scientist was a contemporary of Charles Darwin.

Some of Tyndall’s writings are available via Project Gutenberg