Editing Metal detector (section)

=== First idea ===
The first metal detector was likely the simple electric conduction metal detector ca. 1830.<ref>{{Cite web|url=https://goldgold.com/history-of-treasure-gold-detectors.html|title=A chronological account of the development of treasure and gold locators from 1830 to 1930.|date=23 November 2011 }}</ref> Electric conduction was also used to locate metal ore bodies by measuring the conductivity between metal rods driven into the ground.

In 1862, Italian General [[Giuseppe Garibaldi]] was wounded in the foot. It was difficult to distinguish between bullet, bone, and cartilage. So Professor Favre of Marseilles quickly built a simple probe that was inserted into the track of the bullet. It had two sharp points connected to a battery and a bell. Contact with metal completed the circuit and rang the bell.<ref>''Morning Herald (London)'', 1862 Nov 13, p. 5</ref> In 1867, Mr. Sylvan de Wilde had a similar detector and an extractor also wired to a bell.<ref>[https://babel.hathitrust.org/cgi/pt?id=hvd.32044103082012&view=1up&seq=463 "An ingenious bullet detector "], ''The Lancet'', 1867 July, p. 457</ref>
In 1870, [[Gustave Trouvé]], a French electrical engineer also had a similar device however his buzzer made a different sound for lead and iron.<ref>[https://babel.hathitrust.org/cgi/pt?id=nnc1.cu05649617&view=1up&seq=55 "A new method of probing wounds"], ''American artisan'', 1870 Jan 19, p. 45</ref>
The electric bullet locators were in use until the advent of X-rays.