Inventing a telephone

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Match the following words and word expressions with their definitions.

1. frequency	A) a special network, one that has one closed loop giving a return path for the current
2. amplitude	B) a metal that has been drawn into a very long, thin thread or rod
3. liquid transmitter	C) the height of the wave
4. current	D) a water microphone or water transmitter based on Ohm’s law
5. circuit	E) number of cycles per a unit of time
6. wire	F) a flow of electric charge

“Mr. Watson, come here, I want you.” With these words, spoken by inventor Alexander Graham Bell into his experimental telephone on March 10, 1876, an industry was born. For down the hall, Bell’s assistant, Thomas Watson, distinctly heard Bellutter the first spoken sentence ever transmitted via electricity. That achievement was the culmination of an invention process Bell had begun at least four years earlier.

In the 1870s, electricity was the cutting-edge technology. Like today’s Internet, it attracted bright, young people, such as Bell and Watson, who were only 29 and 22 in 1876. The field of electricity offered them the opportunity to create inventions that could lead to fame and fortune.

There was already one great electrical industry — the telegraph, whose wires crossed not only the continent but even the Atlantic Ocean. The need for further innovations, such as a way to send multiple messages over a single telegraph wire, were well known and promised certain rewards. But other ideas, such as a telegraph for the human voice, were far more speculative. By 1872, Bell was working on both voice transmission and a “harmonic telegraph” that would transmit multiple messages by using musical tones of several frequencies

The telegraph transmitted information by an intermittent current. An electrical signal was either present or absent, forming the once-familiar staccato of Morse code. But Bell knew that sounds like speech were complex, continuous waves, with not only tone but amplitude. In the summer of 1874, while visiting his parents in Brantford, Ontario, Bell hit upon a key intellectual insight: To transmit the voice electrically, one needed what he called an “induced undulating current.” Or to put it another way, what was required was not an intermittent current, but continuous electrical waves of the same form as sound waves.

On July 1, 1875, Bell succeeded in transmitting speech sounds, but they weren’t intelligible. He returned to his experiments in Boston. On March 10, he hooked up his latest design, known as the liquid transmitter, into an electrical circuit, and Watson heard Bell’s voice.

Bell announced his discovery, first in lectures to Boston scientists and then at the Philadelphia Centennial Exposition to a panel of notables including Brazilian Emperor Dom Pedro II and eminent British physicist William Thomson. The emperor exclaimed, “My God! It talks!” Thomson took news of the discovery across the ocean and proclaimed it “the greatest by far of all the marvels of the electric telegraph.”

Alexander Graham Bell had little interest in being a businessman. In July 1877, he married Mabel Hubbard, and set sail for what proved a long honeymoon in England. He left the growing business to Hubbard and Sanders, and went on to a long productive career as a scientist and inventor.

But from the telephone’s earliest days, Bell understood his invention’s vast potential. He wrote in 1878: “I believe in the future wires will unite the head offices of telephone companies in different cities, and a man in one part of the country may communicate by word of mouth with another in a distant place.”

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