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Great Scientists and their Inventions

Alexander Graham Bell (1847-1922.)

alexander graham bell

image source: wikimedia commons

Alexander Graham Bell invented the telephone. Remarkably, he only worked on his invention because he misunderstood a technical work he had read in German. His misunderstanding ultimately led to his discovery of how speech could be transmitted electrically.

The Invention of the Telephone

While he was moving jobs and locations around the UK and North America, Bell had developed an overriding desire to invent a machine that could reproduce human speech.

Speech had become his life: his mother had gone deaf, and Bell’s father had developed a method of teaching deaf people to speak, which Bell taught. His research into mechanizing human speech had become a relentless obsession: in the UK it had driven him almost to collapse.

When Bell was only 19 years old, he had described the work was doing in a letter to the linguistics expert Alexander Ellis. Ellis told Bell his work was similar to work carried out in Germany by Hermann von Helmholtz.


Patenting the Telephone

Aged 27, in 1875, Bell and his investors decided the time had come to protect his intellectual property using patents.

Bell had a patent written for transmission of speech over an electrical wire. He applied for this patent in the UK, because in those days UK patents were granted only if they had not first been granted in another country. Bell told his attorney to apply in the USA only after the patent had been granted in the UK.

By 1876, things in the USA had become murkier. In February of that year, Elisha Gray applied for a US patent for a telephone which used a variable resistor based on a liquid: salt water.

In the transmitter, the liquid resistor transferred to an electric circuit the vibrations of a needle attached to a diaphragm which had been made to vibrate by sound. The electrical resistance of the circuit changed in tandem with the needle’s position in the liquid, and so sound was converted into an equivalent electrical signal. The receiver converted the electrical signal back into sound using a vibrating needle in liquid connected to a diaphragm which vibrated to recreate the sound that had been transmitted.

On the same day, Bell’s attorney filed his US patent application.



It was only in March 1876 that Bell actually got his invention to work, using a design similar to Gray’s. Hence Gray lay claim to have invented the telephone.

On the other hand, Bell had established the concept before Gray, and in all demonstrations of a working phone Bell gave or developed commercially he used his own setup rather than a water based variable resistor. In fact, in 1875, Bell had filed a patent for a liquid mercury based variable resistor, predating Gray’s liquid variable resistor patent.

Bell had to fend off around 600 lawsuits before he could finally rest in bed at night as the legally acknowledged inventor of the telephone.


“Mr. Watson, come here. I want to see you.”

THE FIRST WORDS SPOKEN IN A TELEPHONE CALL: ALEXANDER GRAHAM BELL


The Metal Detector

In 1881, after President James Garfield was shot, Bell invented the metal detector to locate the bullet precisely. The rudimentary metal detector worked in tests, but the bullet in the President’s body was too deep to be detected by the early detecting equipment.


National Geographic Society

In 1888 Bell was one of the founders of the National Geographic Society. In 1897, he became its second president.


Death

Alexander Graham Bell died aged 75 on August 2, 1922 in Nova Scotia, Canada. He had been ill for some months with complications from diabetes. He was survived by his wife, Mabel, and two daughters – Elsie and Marian.

Every phone in North America was silenced during his funeral in his honour.

The unit of sound intensity, the bel, more usually seen as the smaller unit, the decibel, was named after Bell: it was conceived of in the Bell Laboratories.


Quotes:

When one door closes another door opens; but we so often look so long and so regretfully upon the closed door, that we do not see the ones which open for us.

Concentrate all your thoughts upon the work at hand. The sun's rays do not burn until brought to a focus.

A man, as a general rule, owes very little to what he is born with - a man is what he makes of himself.