This image was acquired from
wikimedia. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Bells Photophon Schema. en Alexander Graham Bell's photophone technical drawing by Bell org BellsPhotophonSchema Meyers Konversationslexikon von on German PDold Alexander Graham Bell Photophone
Page 2023 Free-images.com. All images are Public Domain