Bell, Alexander Graham. The Discovery of the Spectrophone. p. 142-162. From the Bulletin of the Philosophical Society of Washington, Vol. IV, 1881. 8vo. Original wrappers. With illustrative plates showing the diagrams of the spectrophone. FIRST EDITION. While Bell was experimenting with long-distance sound transmission via the photoacoustic effect with the photophone, he recognized that the photoacoustic effect had applications in spectroscopy, Bell developed the spectrophone, essentially an ordinary spectroscope equipped with a hearing tube instead of an eyepiece. Bell applied this effect for spectral identification of materials and found that materials exposed to the non-visible (ultra-violet and infra-red) portions of the solar spectrum can also produce sounds.

Minor chipping and loss to wraps and spine.