Right across the street from where I am now working at 13th and K St, nw. there is a wonderful old building dating to the mid 1800's that was part of the EC school system after the end of the civil war called the Franklin School. In doing some research on it as old building have always interested me, I discovered a pretty interesting bit of DC history. It seems that Alexander Bell had his first DC laboratory at 1325 L street and in during the spring/summer of 1880 he and assistant conducted the first successful wireless transmissions of the human voice from the roof of the Franklin School to his lab some 700 feet away, using a Beam of Light! This was some 19 years before the radio phone using radio waves was successfully tested. Who knew! And even more interesting was the fact that his first trials for using light to transmit sound wirelessly didn't even employ electricity, it was all mechanical. He considered it his most important invention and little could he have imagined that 100 years later Optical fiber would start to be used as a transmission medium of choice. I didn't even know his labs were in DC. The laboratory was later moved to Conn. Ave where it was called the Volta Laboratory after he won the Volta Award in Paris for his work with electricity.
Pretty Kool if you ask me!
Link to an article about it below.
https://en.wikipedia.org/wiki/Photophone
RM