🔗 Heliograph - Wikipedia, the free encyclopedia
This bookmark is very old and the link may no longer work. Try this archived link from the Internet Archive:
🗃️ https://web.archive.org/web/*/http://en.wikipedia.org/wiki/Heliograph
A heliograph is a wireless solar telegraph that signals using Morse code flashes of sunlight reflected by a mirror. http://is.gd/vgK5dW