Three days after filing his telephone patent, Alexander Graham Bell successfully transmitted speech to an assistant in another room of their Boston workshop. The device converted sound into an electrical signal that could be reproduced at a distance, a breakthrough that would spawn a global communications industry within a generation.
Alexander Graham Bell had filed his telephone patent on March 7, 1876, and just three days later he proved the concept actually worked. Working late in a rented room on Court Street in Boston, Bell spilled acid from a battery on his trousers and, in the next room, shouted for his assistant Thomas Watson through the experimental transmitter: "Mr. Watson, come here, I want to see you." Watson heard the words clearly through the receiver and came running, not to help with the accident but in astonishment that the machine had worked.
The device used a liquid transmitter, a needle dipped in acidified water that vibrated with sound waves and varied electrical resistance accordingly. It was crude and short-lived as a design, but it proved that the human voice could be converted into an electrical signal and reconstructed intelligibly elsewhere. Bell had beaten rival inventor Elisha Gray to the patent office by hours, a coincidence that fueled decades of litigation.
Within two years, telephone exchanges opened in New Haven and London. Bell's stumbling accident and honest cry for help became, by accident, the opening line of an industry that would eventually connect billions of people.
Key people: Alexander Graham Bell, Thomas Watson