"If you open a piano and sing into it, a certain string will respond. Change the pitch of your voice; the first string ceases to vibrate, but another replies. Change again the pitch; the first two strings are silent, while another sound resounds. Thus is sentient man acted on by nature, the optic, the auditory, and other nerves of the human body being so many strings differently tuned, and responsive to different forms of the universal power."
John Tyndall, 'Radiation', part 2, in Fragments Of Science; A Series Of Detached Essays, Addresses And Reviews, 7th ed, 2 vols, 1889