JOHN TYNDALL SIGNED NOTE, "To the Revd. Jesse S. Gilbert, from John Tyndall", 4 x 2.25, by Irish natural philosopher, chemist, physicist, mountaineer, author. In fine condition, with light age toning and mounting remnant on the reverse which does not show through.
John Tyndall (1820-1893) answered the age old question of youngsters by showing that the sky is blue because of fine particles in the atmosphere. He studied the diffusion of light by large molecules and dust, which became known as the Tyndall effect. He also made an extended and serious investigation of glacier motion, was a pioneer mountaineer who's expeditions became legendary, his investigations of the transparency and opacity of gases and vapors for radiant heat is considered his chief scientific work, his 1875 report to the Royal Society of the discovery of antibiotic properties of penicillium predated Alexander Fleming by over 50 years, and on the controversy of science and religion he played and important part in educating the public mind regarding church dogma and religious authority.