Wilhelm Röntgen

Röntgen, Wilhelm Conrad (1845-1923)

Wilhelm Conrad Röntgen (1845-1923) was a German physicist.

Though not a medical doctor as such, the physicist Wilhelm Röntgen made a ground-breaking discovery which would change the landscape of clinical medicine forever.

On November 8, 1895 he produced and detected electromagnetic radiation in a wavelength range he termed X-rays; later eponymously termed Röntgen rays.

The Nobel Prize in Physics for 1901 was awarded to Wilhelm Conrad Röntgen “in recognition of the extraordinary services he has rendered by the discovery of the remarkable rays subsequently named after him.”

I didn’t think; I investigated.

Röntgen 1896

  • Born on March 27, 1845 in Lennep, Germany
  • 1862 – Expelled from technical school in Utrecht, Netherlands
  • 1865-1869 Completed PhD at the University of Zurich. Thesis: Studien über Gase [Studies on gases]
  • 1870 – Appointed assistant to prominent physicist August Kundt (1839-1894); moved to Würzburg with him
  • 1872 – Married Bertha Ludwig with whom he fathered no children. The pair adopted a daughter
  • 1874 – Lecturer at the university of Strasbourg
  • 1879 – Chair of physics at the university of Giessen
  • 1888 – Chair of physics at the university of Würzburg
  • 1895 – Studied cathode rays, leading to the discovery of X-rays on November 8, 1895 and the first human radiograph (the hand of his wife, Bertha) on December 22, 1895 –  ‘Hand mit Ringen
  • 1896 – Published his findings as Ueber eine neue Art von Strahlen [On a new type of rays]
  • 1900 – Chair of Physics at the university of Munich, where he remained the rest of his life
  • 1901 – Received the first ever Nobel Prize in Physics. Röntgen donated the 50,000 Swedish krona reward for research research at the University of Würzburg.
  • Awards: Rumford Medal (1896); Matteucci Medal (1896); Elliott Cresson Medal (1897); Barnard Medal for Meritorious Service to Science (1900); Nobel Prize for Physics (1901);
  • Died on February 10, 1923 from colorectal cancer. All his personal and scientific correspondence was destroyed after his death in accordance with his will.

Medical Eponyms
Röntgen rays (1895)

Röntgen made a ground-breaking discovery which would change the landscape of clinical medicine forever the Röntgen rays, or X-rays.

Röntgen’s discovery was based on cathode rays, which had been the subject of investigation by fellow physicists Heinrich Hertz (1857-1894) and Philipp Lenard (1862-1947). Cathode rays became the centre of attention of research in the latter half of the 19th century, when the photoelectric effect was first demonstrated, by passing a high voltage through a vacuum-pumped tube with a heated filament. 

On November 8th 1895, Röntgen was experimenting with cathode rays, and sealed one such discharge tube in a cardboard box. On passing current through the tube, he noticed that a nearby plate covered on the one side with barium platinocyanide was lighting up fluorescently. The cardboard box was completely impenetrable to light, and so Röntgen hypothesized that another type of ray, termed X-ray, must be emitted.

1. Lässt man durch eine Hittorf’sche Vacuumröhre, oder einen genügend evacuirten Lenard’schen, Crookes’schen oder ähnlichen Apparat die Entladungen eines grösseren Ruhmkorff’s gehen und bedeckt die Röhre mit einem ziemlich eng anliegenden Mantel aus dünnem, schwarzem Carton, so sieht man in dem vollständig verdunkelten Zimmer einen in die Nähe des Apparates gebrachten, mit Bariumplatincyanür angestrichenen Papierschirm bei jeder Entladung hell aufleuchten, fluoresciren, gleichgültig ob die angestrichene oder die andere Seite des Schirmes dem Entladungsapparat zugewendet ist. Die Fluorescenz ist noch in 2 m Entfernung vom Apparat bemerkbar.

Man überzeugt sich leicht, dass die Ursache der Fluorescenz vom Entladungsapparat …

2. Das…Auffallende ist, dass durch die schwarze Cartonhülse, welche keine sichtbaren… Strahlen… durchlässt, ein Agens hindurchgeht, das im Stande ist, lebhafte Fluorescenz zu erzeugen

**Der Kürze halber möchte ich den Ausdruck „Strahlen“ und zwar zur Unterscheidung von anderen den Namen „X-Strahlen“ gebrauchen.

14. Die Berechtigung, für das von der Wand des Entladungsapparates ausgehende Agens den Namen „Strahlen“ zu verwenden, leite ich zum Theil von der ganz regelmässigen Schattenbildung her, die sich zeigt, wenn man zwischen den Apparat und den fluorescirenden Schirm (oder die photographische Platte) mehr oder weniger durchlässige Körper bringt.

1. If one discharges a Ruhmkorff (induction coil) through a Hittorf vacuum tube, or a sufficiently evacuated Lenard, Crookes or similar apparatus (Vacuum Tube), and covers the tube with a tightly fitting case of thin, black cardboard, then one can see in the completely darkened room, a paper plate painted in barium platinocyanide light up brightly, fluorescently, whether the painted side of the plate be pointed towards, or away from the discharge apparatus. The fluorescence is still noticeable up to 2m away.

One is easily convinced, that the cause of the fluorescence is coming from the discharge apparatus…

2. What is noticeable is that the black cardboard sleeve, which does not allow any visible rays to escape, is penetrated by an agent which is capable of creating vivid fluorescence

**For the sake of brevity, I would like to use the term “rays” and to distinguish it from others the name “X-rays“.

14. The justification for using the name “rays” for the agent emanating from the wall of the discharge apparatus I derive in part from the very regular formation of shadows which appears when one is placed between the apparatus and the fluorescent screen (or the photographic one Plate) brings more or less permeable bodies.

This discovery took the scientific and medical world by storm. Within weeks X-rays were being applied to both diagnostic and therapeutic medicine. The speed with which this ‘new discovery’ was taken up is quite astonishing. In an age without social media, smartphones and live-streaming; news of the discovery rapidly spanned the globe.

"Is it light?"
"Is it electricity?"
"Not in any known form."
"What is it?"
"I don't know."

And the discoverer of the X rays thus stated as calmly his ignorance of their essence as has everybody else who has written on the phenomena thus far.

Röntgen. Interview with HJW Dam April 1896: 413

1896 – In June, six months after Röntgen’s discovery, Leopold Freund (1868–1943) of the University of Vienna effected the first cure of skin cancer in a 5 year-old patient by means of X-rays generated by a Hittorf tube

1905 – The German radiological society [Deutsche Röntgengesellschaft eV] was founded by Heinrich Albers-Schönberg

Other eponyms

Röntgenbild: the German term for “X-ray film” to this day

Röntgengesellschaft: the German radiological society

Röntgen unit: the original measure of radiation exposure; now replaced by the Gray unit

6401 Röntgen: an asteroid measuring 7.9km discovered in 1991. Takes 1600 days to orbit the sun

ICE 884 Röntgen: German high-speed train involved in a de-railing accident killing 101 people. The name was removed following the accident

Roentgenium (2004): Synthetic chemical element with symbol Rg and atomic number 111 created in 1994 by the GSI Helmholtz Centre for Heavy Ion Research and eponymously attributed to Wilhelm Röntgen by the International Union of Pure and Applied Chemistry (IUPAC) in 2004


Röntgen, who today is widely described in literature as a modest man, more intereseted in his scientific enquiries than in the publicity that was associated with them, was despised by fellow german physicist Philip Lenard. Though it is recognized that Röntgen used a Hittorf-style vacuum tube on the night of his famous discovery, Lenard claimed that the discovery was made with one of his own tube designs. 

Lenard himself was an early member of the Nazi party, and a staunch anti-semite, central in the purging of the german scientist field of Jews (including the likes of Einstein). Röntgen, though not Jewish, was considered to have been friendly to Jews, and as such the Third Reich assigned credit for the discovery of X-rays to Lenard. 

There were however some key differences in the experimental setup between the two colleagues, which meant that Röntgen was correctly attributed the eponymous discovery. Lenard, hoping to demonstrate the photographic effects of cathode rays, used a tube wrapped in zinc (relatively impermeable to X-rays), and a plate coated in keton (inorganic substance which does not fluoresce in the presence of X-rays).

Röntgen on the other hand chose his setup to be with a cardboard casing, and a Barium Platinocyanide (organic substance) plate- reportedly as he was still waiting on the arrival of his order of keton! This difference however meant, that the subtle X-rays emitted were able to penetrate the cardboard casing, and cause the plate to fluoresce!

Major Publications



Eponymous terms


Resident medical officer in emergency medicine MB ChB (Uni. Dundee)  MRCS Ed. Avid traveller, yoga teacher, polylinguist with a passion for discovering cultures.

BA MA (Oxon) MBChB (Edin) FACEM FFSEM. Emergency physician, Sir Charles Gairdner Hospital.  Passion for rugby; medical history; medical education; and asynchronous learning #FOAMed evangelist. Co-founder and CTO of Life in the Fast lane | Eponyms | Books | Twitter |

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