Mr. Watson, of course, was Thomas Watson, a mechanic who had a knack for making reality out of theory. He and Bell worked on the "multiple harmonic telegraph" for many weeks before Bell had the idea to develop a telephone. The first device to transmit speech vibrations electrically between two receivers was successfully tested in June 1875. No one could understand anything as words, but the sounds did go through.

The following February, Bell filed his application in the U.S. patent office, mere hours before a similar filing by Elisha Gray, another inventor. If not for those few hours, we might have had Gray Telephone all these years.

Bell was granted his patent on March 7, and the fateful call to Watson was made on March 10, at Bell's home in Boston. Public demonstrations followed, including one over a two-mile distance from Boston to Cambridgeport. The following year, the Bell Telephone Company came into existence. The rest is history.