Previous part (Introducton to AG Bell)

How the telephone came about

Bell had been experimenting for some time with a device he called a "Harmonic Telegraph". A device which was intended to transmit several messages by Morse code simultaneously - probably the first use of Frequency Division Multiplexing - a method of using different frequencies to carry several independent streams of communication simultaneously over the same channel. FDM would later become fundamental to all sorts of telecommunications, in particular the broadcasting of multiple TV and radio stations as well as a way to make more efficient use of telephone lines. In fact, your DSL broadband line relies on FDM to allow it carry high speed data and phone calls at the same time.

Bell had enlisted a Boston based engineering company to make the prototypes for his Harmonic Telegraph, and the employee assigned to build them was Dr. Thomas Watson. One day Bell came charging into Watson's workshop with a part from his Harmonic Telegraph. It had not been made as he had intended and rather than stopping at the front desk, Bell went straight to the engineer assigned to it. Bell already had a customer for his Harmonic Telegraph - the Atlantic & Pacific Telegraph Company, pretty much guaranteeing him great riches except for one problem...he couldn't get the thing to work properly. In retrospect this was perhaps something of a blessing, for had it worked, he most probably would not have stumbled upon the basis for the telephone.

Bell and Watson were to spend many hours, typically in the early morning, working on the Harmonic Telegraph and Bell would frequently regale Watson with grand ideas of theories and devices he could envisage. Watson was used to wannabe entrepreneurs coming into the workshop with their hair brained schemes many of which were doomed to failure and Watson had learned to take them with a pinch of salt, but one idea of Bells so captivated Watson he could remember for the rest of his life the exact words Bell used to introduce it:

"If I could make a current of electricity vary in intensity, precisely as air varies in density during the production of sound, I should be able to transmit speech telegraphically"

The majority of people however, including Bells' financial backers and even Watson himself believed the apparatus envisaged by Bell would be far too costly to produce and that time would be better spent perfecting the Harmonic Telegraph. Watson described this period as a "nightmare" - the Harmonic Telegraph refused to work correctly and both Watson and Bell became increasingly frustrated and discouraged.