In 1854, John Tyndall demonstrated to the Royal Society that light could be conducted through a curved stream of water, proving that a light signal could be bent. In 1880, Alexander Graham Bell invented his "Photo phone" which transmitted a voice signal on a beam of light. Bell focused sunlight with a mirror and then talked into a mechanism that vibrated the mirror. At the receiving end, a detector picked up the vibrating beam, and decoded it back into a voice, the same way a phone did with electricity. Many things, a cloudy day for instance ....