Editing Nikola Tesla (section)

=== X-ray experimentation ===
[[File:X-Ray Photograph of Tesla's left hand.jpg|left|thumb|X-ray Tesla took of his hand]]

Starting in 1894, Tesla began investigating what he referred to as [[radiant energy]] of "invisible" kinds after he had noticed damaged film in his laboratory in previous experiments<ref>{{cite book|last1=Tesla|first1=Nikola|title=X-ray vision: Nikola Tesla on Roentgen rays|date=2007|publisher=Wiilder Publications|location=Radford, VA|isbn=978-1-934451-92-2|edition=1st}}</ref> (later identified as "Roentgen rays" or "[[X-rays]]"). His early experiments were with [[Crookes tube]]s, a [[cold cathode]] electrical discharge tube. Tesla may have inadvertently captured an X-ray image—predating, by a few weeks, [[Wilhelm Röntgen]]'s December 1895 announcement of the discovery of X-rays—when he tried to photograph Mark Twain illuminated by a [[Geissler tube]], an earlier type of gas discharge tube. The only thing captured in the image was the metal locking screw on the camera lens.{{sfn|Cheney|2001|p=134}}

In March 1896, after hearing of Röntgen's discovery of X-ray and X-ray imaging ([[radiography]]),<ref>RADIOGRAPHY – EXPERIMENTS MADE BY NIKOLA TESLA – Shoulder of a Man Taken Through His Clothing—Chalky Deposits Infallibly Detected, The Constitution, Atlanta, Georgia, Friday 13, March 1896,  p. 9 [http://anengineersaspect.blogspot.com/2011/07/nikola-tesla-radiography-experiments.html online archive] {{Webarchive|url=https://web.archive.org/web/20131004213023/http://anengineersaspect.blogspot.com/2011/07/nikola-tesla-radiography-experiments.html |date=4 October 2013 }}</ref> Tesla proceeded to do his own experiments in X-ray imaging, developing a high-energy single-terminal [[vacuum tube]] of his own design that had no target electrode and that worked from the output of the Tesla coil (the modern term for the phenomenon produced by this device is ''[[bremsstrahlung]]'' or ''braking radiation''). In his research, Tesla devised several experimental setups to produce X-rays. Tesla held that, with his circuits, the "instrument will&nbsp;... enable one to generate Roentgen rays of much greater power than obtainable with ordinary apparatus".<ref>{{cite book |first=Nikola |last=Tesla |url=http://www.tfcbooks.com/tesla/1898-11-17.htm |chapter=High Frequency Oscillators for Electro-Therapeutic and Other Purposes |title=Proceedings of the American Electro-Therapeutic Association |publisher=American Electro-Therapeutic Association |page=25 |date=17 November 1898 |access-date=27 January 2009 |archive-date=1 January 2016 |archive-url=https://web.archive.org/web/20160101011808/http://www.tfcbooks.com/tesla/1898-11-17.htm |url-status=live }}</ref>

Tesla noted the hazards of working with his circuit and single-node X-ray-producing devices. In his many notes on the early investigation of this phenomenon, he attributed the skin damage to various causes. He believed early on that damage to the skin was not caused by the Roentgen rays, but by the [[ozone]] generated in contact with the skin, and to a lesser extent, by [[nitrous acid]]. Tesla incorrectly believed that X-rays were longitudinal waves, such as those produced in [[waves in plasmas]]. These plasma waves can occur in [[force-free magnetic field]]s.<ref>Griffiths, David J. ''Introduction to Electrodynamics'', {{ISBN|0-13-805326-X}} and Jackson, John D. ''Classical Electrodynamics'', {{ISBN|0-471-30932-X}}.</ref><ref>{{cite book |title=Transactions of the American Electro-therapeutic Association |publisher=American Electrotherapeutic Association |year=1899 |page=16 |url=https://books.google.com/books?id=bUo7vYNkbKQC |access-date=25 November 2010 |archive-date=23 March 2024 |archive-url=https://web.archive.org/web/20240323123806/https://books.google.com/books?id=bUo7vYNkbKQC |url-status=live }}</ref>

On 11 July 1934, the ''[[New York Herald Tribune]]'' published an article on Tesla, in which he recalled an event that occasionally took place while experimenting with his single-electrode vacuum tubes. A minute particle would break off the cathode, pass out of the tube, and physically strike him:<ref name=Anderson>{{cite book |last=Anderson |first=Leland |title=Nikola Tesla's teleforce & telegeodynamics proposals |year=1998 |publisher=21st Century Books |location=Breckenridge, Colo. |isbn=0-9636012-8-8}}</ref>
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Tesla said he could feel a sharp stinging pain where it entered his body, and again at the place where it passed out. In comparing these particles with the bits of metal projected by his "electric gun", Tesla said, "The particles in the beam of force&nbsp;... will travel much faster than such particles&nbsp;... and they will travel in concentrations".
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