[T]he atmosphere admits of the entrance of the solar heat, but checks its exit; and the result is a tendency to accumulate heat at the surface of the planet.
Many online citations seem to attribute this quote (or so it appears) to a talk he gave in 1859 that was published in 1861 under the title “On the Absorption and Radiation of Heat by Gases and Vapours, and on the Physical Connexion of Radiation, Absorption and Conduction”. But this is not the correct citation.
The correct citation is John Tyndall, “On the transmission of heat of different qualities through gases of different kinds”, from the Weekly Evening Meeting of June 10, 1859, published in Notices of the Proceedings at the Meetings of the Royal Institution of Great Britain, Vol. III (1858-1862), pages 155-158. (The quote above appears on page 158.)
Here is the Google Book version.