GENIUS at WORK
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.
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.
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