Alexander Graham Bell – Inventor of the First Metal Detector?

John —  21 February 2012 — 15 Comments


Alexander Graham Bell - Wikimedia Commons Licence

In many people’s minds Alexander Graham Bell is remembered and credited for inventing the telephone, but (and I hadn’t fully realised) there was much more to the man than that!

In 1885, nine years after his invention, Bell and his wife paid a visit to Baddeck on Nova Scotia’s Cape Breton Island. They fell in love with the landscape, and soon returned to build a house and laboratory where he would spend his summers for the next 37 years. At Baddeck, Bell experimented in many fields, including the development of a successful hydrofoil.

The Alexander Graham Bell Historic Site in Baddeck, Nova Scotia. Click to Enlarge

In the summer of 2002 I visited the beautiful 25-acre Alexander Graham Bell national historic site in Baddeck. The complex, with its three exhibit halls, contains the largest collection of Bell’s artefacts and inventions where I was reminded of his metal detecting exploits.

In 1881 Bell was said to have invented the first metal detector, adapted from the telephone, which he called the ‘bullet probe’. The device was hurriedly put together in an attempt to find an assassin’s bullet lodged in the body of the American president James Garfield. X-rays were unknown at that time. The hope was that Bell’s invention would find the bullet so it could be removed, thus saving Garfield’s life.

The detector consisted of two coils of insulated wire, a battery, a circuit breaker, and, of course, Bells’ telephone. The illustration below shows Bell’s sketch of the device. The ends of the primary coil were connected to a battery and those of the secondary coil were fastened to posts of the telephone. When a piece of metal was placed by the circuit breaker, a hum could be heard in the telephone receiver.

Drawing of Bell’s Metal Detector – America’s Library

Hasty experiments finding spent bullets in bags of grain, buried in sides of beef and on Civil War veterans who still had ammunition in their body. Various adjustments were made before they put the device to the ultimate test.

The results of the experiment were inconclusive as there was a faint hum no matter where the wand was placed on the president’s body. The apparatus was tested a second time, but it was the same again. No matter where they placed the detector wand on the president’s body, a faint hum could be heard. When they moved the wand away, the hum could no longer be heard. All were stumped. It worked fine on everyone else but the president.

Isn’t hindsight a wonderful thing? So what is the answer to why Bell’s invention worked on everyone except the President? It wasn’t the president that was the problem – it was the bed he was in. Coil sprung mattresses had just been invented. The detector was detecting metal – unfortunately they didn’t realise that it was the coil springs.

If they had moved him off the bed to the floor or table, their apparatus would have detected where the bullet was and likely, knowing this, the White House surgeons could have saved James Garfield.


Graham Bell had an insatiable thirst and curiosity for sound, speech and problem solving. His first invention was a wheat-husking machine he built at age 11. He made significant improvements in the realm of sound technology including the telegraph, the photophone, and the phonograph. Though his interests and expertise did not stop with the progression of sound and speech. He invented the metal detector in 1881 as an attempt to locate the bullet in U.S. President James Garfield.

He constructed a breathing apparatus as a result of the loss of his two prematurely born sons. This invention led to the development of the Iron Lung. His interests in hydrofoils led to the construction of many hydrofoil watercrafts. His interest in aerodynamics paved the way to the building of several tetrahedral kites and AEA’s Silver Dart engine in 1909. He also made significant advances in resource conservation.

from 2010 The Telephone

The Book I Bought in Baddeck

© Adapted from a previously published Searcher article. Thanks also to the History Buff for additional information.

Also available in other languages. :-)


Alexander Graham Bell’s first sound recordings restored to life. Listen to a recording made in 1881 by clicking HERE 


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15 responses to Alexander Graham Bell – Inventor of the First Metal Detector?

  1. Great story, and it took a Brit to make me aware of it. I am ashamed of myself. Thank you John Winter….need to share this if I may?

  2. Reminds me of a friend that was retiring and planned to live in the Caribean. He decided that a metal detector would be great on the beach. He bought a matching pair for himself and his wife. Out they went to test. Every step he took he had a signal but nothing there when he dug. He changed detectors with his wife and the same thing happened. It was almost an hour before he realised he was wearing steel toecap boots.

  3. Very interesting.
    All educating stuff John.

  4. Interesting read John, I was aware of his findings, he was a pioneer in many induction related electronic experiments back in the day, Read lots about the man when I was studying radio and electronics many moons ago lol.

  5. Thanks for adding the recording. Now that I hear his voice I do indeed know the man….

  6. I’ve just heard some of the Brit awards and now I am thinking why did he invent the phonograph.

  7. I’m doing a research of Alexander Graham Bell

  8. You can also check out the January – February issue of Relic Hunter Magazine, “A History of Metal Detecting”, which carries the Bell Story, and lots of extras.

  9. Jakob Øhlenschlæger 1 April 2012 at 1:40 am

    When it comes to the history of metal detecting Bell is sometimes mentioned and then WW II next. WW I shouldn’t be forgotten as this little piece from 1917 shows: . Same website features a good article on Bell and other pioners as well: .

    Of course, as a Dane I have to point out that we would be nowhere without Hans Christian Ørsted :)

    • Thank you for your invaluable contribution Jacob, and also for introducing me to Hans Christian Ørsted. So. he’s the guy responsible for all the aluminium I find when detecting! :-) Or, should I be blaming the great British scientist and inventor, Humphry Davy?

  10. Arthur J Fleming 4 September 2013 at 6:57 am

    Very entertaining as well as educational post. I did not realize his other contributions other than the telephone. I am going to have to place him up there with Thomas Alva Edison, now. Thanks, Artie

  11. Hey !

    Yes, it´s so true – A.G. Bell invented the metal detector / metalldetektor ! :)
    Great man with great ideas :)


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