I have been reading about the photophone, another invention by alexander graham bell. You know the name because he invented the telephone. But he also invented the photophone, a strange machine that allows the transmission of speech on a beam of light. He apparently was so excited about this, he says its one of the 'greatest inventions he has ever made, greater than the telephone'. Its strange to me, and I have used it in talks as an example of a technology invented for a purpose but now re-used for another entirely different purpose. Its also just a wild idea. He took sunlight and bounced it off a mirror attached to a microphone, this changes how bright the light is and where it focused, he then sent this light to a reciever, which vibrated according to the light and then recreated back the sound so as someone could hear. It obviously didn't take over from the telephone, but it did, for the first time ever, utilize the photo-acoustic effect, something that in the past ten years has been used to make a new technology to visualize peoples insides similar to an ultrasound, just excited by light. Thus, the invention failed back in the day, but just didn't have its right application. There are probably so many lost inventions out there, just waiting to be found.