photophone principle - AERNOUDT JACOBS
According to Alexander Graham Bell, the photophone, not the telephone, was his greatest invention. The photophone is a telecommunications device that allows transmission of speech on a beam of light. - iFunny
Photophone - Wikipedia
Optics
NICHION from Osaka and it's successor TOSHIBA PHOTO PHONE – 日本からの映写機 Motion Picture Projectors from Japan
File:Photophone.jpg - Wikimedia Commons
Alexander Graham Bell and the Invention of the Photophone
Alexander graham bell with photophone hi-res stock photography and images - Alamy
Photophone - Wikipedia
RCA Photophone - M HKA Ensembles
History and Physics: The Photophone (A cell phone in the 1800's) - YouTube
Photophone Transmitter, Bell and Tainter, 1881 - Stock Image - C033/4513 - Science Photo Library
Geemarc PhotoPhone 100 Amplified Picture Telephone - AmplifiedTelephones.co.uk
Bells Photophone Transmitter, 1880 Photograph by Science Source - Pixels
GeekCon - Building a Photophone - YouTube
The photophone (optical phone) - Paléo-Energétique
Photophone – Joseph Henry Project
Today in History: Bell's Photophone | Citizen U Primary Source Nexus
Schematized representation of Graham Bell's photophone [5] | Download Scientific Diagram
Drawings of photophone components | Niels Bohr Library & Archives
:max_bytes(150000):strip_icc()/GettyImages-89861170-56b008335f9b58b7d01f9b15.jpg "Alexander Graham Bell and the Photophone")