Wilhelm Röntgen
German experimental physicist (1845–1923)

Wilhelm Röntgen
Röntgen in 1900
Born
Wilhelm Conrad Röntgen

(1845-03-27)27 March 1845
Lennep, Rhine Province, Kingdom of Prussia
Died10 February 1923(1923-02-10) (aged 77)
Munich, Bavaria, Weimar Republic
Citizenship
  • Prussia (until 1848)
  • Stateless (1848–1888)
  • Germany (from 1888)
Alma materUniversity of Zurich (Dr. phil.)
Known forDiscovery of X-rays
Spouse
Anna Bertha Ludwig
​
​
(m. 1872; died 1919)​
Awards
Scientific career
FieldsRadiophysics
Institutions
ThesisStudien über Gase (1869)
Doctoral advisorGustav Zeuner[1]
Other academic advisorsAugust Kundt
Doctoral students
Signature

Wilhelm Conrad Röntgen[a] (27 March 1845 – 10 February 1923)[4] was a German experimental physicist who produced and detected electromagnetic radiation in a wavelength range known as X-rays. For this discovery, Röntgen became the first recipient of the Nobel Prize in Physics in 1901.[5][6]

Biography

Early life and education

The house in Remscheid-Lennep, Germany, where Röntgen was born.

Wilhelm Conrad Röntgen was born on 27 March 1845 in Lennep (now part of Remscheid), Prussia,[7] as the only child of Friedrich Conrad Röntgen, a merchant and cloth manufacturer, and Charlotte Constanze Frowein. In 1848, he moved with his parents to the Netherlands—where his mother's family lived—rendering him stateless.[8][9]

In 1862, Röntgen enrolled at Utrecht Technical School,[8] where he followed courses for almost two years.[10] In 1865, he was unfairly expelled from the Technical School when he was falsely accused of drawing a caricature of one of the teachers, which was actually drawn by someone else.[11]

Without a high school diploma, Röntgen could only attend university in the Netherlands as a visitor. In 1865, he tried to attend Utrecht University without having the necessary credentials required for a regular student. He then moved to Switzerland and passed the entrance examination of the Federal Polytechnic School in Zurich (now ETH Zurich), where he became a mechanical engineering student. In 1869, he received his Ph.D. from the University of Zurich.[8] At the university, Röntgen was the favorite student of Professor August Kundt—whom he followed to the University of Würzburg after graduating, then to the University of Strassburg in 1873.[12]

Career

In 1874, Röntgen became a lecturer at the University of Strassburg. The following year, he became a professor at the Academy of Agriculture in Hohenheim. In 1876, he returned to Strassburg as Professor of Physics, and in 1879 was appointed to the chair of physics at the University of Giessen. In 1888, he reacquired German citizenship (after being stateless for 40 years)[9] and obtained the physics chair at the University of Würzburg,[13] and in 1900 at the University of Munich, by special request of the Bavarian government.

Röntgen had family in Iowa in the United States and planned to emigrate. He accepted an appointment at Columbia University in New York City and bought transatlantic tickets. However, the outbreak of World War I changed his plans, and he remained in Munich for the rest of his career.[citation needed]

Later life and death

Grave of Wilhelm Röntgen (and relatives) in Alter Friedhof in Giessen.

With the inflation following World War I, Röntgen fell into bankruptcy, spending his final years at his country home in Weilheim.[14]

Röntgen died of colorectal cancer on 10 February 1923 in Munich at the age of 77.[15] In keeping with his will, his personal and scientific correspondence with few exceptions, were destroyed upon his death.[15]: 113 [16] His will included numerous benefactions, including to his hometown of Lennep and the Physical Institute of the University of Würzburg.[17]

Discovery of X-rays

X-ray by Röntgen of Albert von Kölliker's hand.

In 1895, in his laboratory at the Physical Institute of the University of Würzburg, Röntgen was investigating the external effects of passing an electric discharge through various types of vacuum tube equipment—apparatuses from Heinrich Hertz, Johann Hittorf, William Crookes, Nikola Tesla, and Philipp Lenard.[14][18] In early November, he was repeating an experiment with one of Lenard's tubes in which a thin aluminium window had been added to permit the cathode rays to exit the tube but a cardboard covering was added to protect the aluminium from damage by the strong electrostatic field that produces the cathode rays. He knew that the cardboard covering prevented light from escaping, yet he observed that the invisible cathode rays caused a fluorescent effect on a small cardboard screen painted with barium platinocyanide when it was placed close to the aluminium window.[13] It occurred to Röntgen that the Crookes–Hittorf tube, which had a much thicker glass wall than the Lenard tube, might also cause this fluorescent effect.

In the late afternoon of 8 November 1895, Röntgen was determined to test his idea. He carefully constructed a black cardboard covering similar to the one he had used on the Lenard tube. He covered the Crookes–Hittorf tube with the cardboard and attached electrodes to an induction coil to generate an electrostatic charge. Before setting up the barium platinocyanide screen to test his idea, he darkened the room to test the opacity of his cardboard cover. As he passed the induction coil charge through the tube, he determined that the cover was light-tight and turned to prepare for the next step of the experiment. It was at this point that he noticed a faint shimmering from a bench a few feet away from the tube. To be sure, he tried several more discharges and saw the same shimmering each time. Striking a match, he discovered the shimmering had come from the location of the barium platinocyanide screen he had been intending to use next.

Based on the formation of regular shadows, Röntgen termed the phenomenon "rays."[19]: 40  As 8 November was a Friday, he took advantage of the weekend to repeat his experiments and made his first notes. In the following weeks, he ate and slept in his laboratory as he investigated many properties of the new rays he temporarily termed "X-rays," using the mathematical designation ("X") for something unknown. The word for X-ray in German and some languages in Central and Eastern Europe are derived from Röntgen's name[20] (and the associated X-ray radiograms as "Röntgenograms").

At one point, while he was investigating the ability of various materials to stop the rays, Röntgen brought a small piece of lead into position while a discharge was occurring. Röntgen thus saw the first radiographic image: his own flickering ghostly skeleton on the barium platinocyanide screen.

About six weeks after his discovery, Röntgen took a picture (a radiograph) using X-rays of his wife Anna Bertha's hand.[6] When she saw her skeleton, she exclaimed "I have seen my death!"[21] He later took a better picture of his friend Albert von Kölliker's hand at a public lecture.

Röntgen's original paper, Ueber eine neue Art von Strahlen (On a New Kind of Rays), was published on 28 December 1895. On 5 January 1896, an Austrian newspaper reported his discovery of a new type of radiation. He was awarded an honorary M.D. from the University of Würzburg after his discovery. He also received the Rumford Medal of the Royal Society in 1896, jointly with Philipp Lenard, who had already shown that a portion of the cathode rays could pass through a thin film of a metal such as aluminium.[13] He published a total of three papers on X-rays between 1895 and 1897.[22]

Röntgen's analysis and publications stirred enormous excitement among physicists. It led Henri Becquerel to look for connections with phosphorescence, leading to his discovery of spontaneous radioactivity in 1896. Marie and Pierre Curie were also taken by the X-ray work but upon hearing of Becquerel findings they returned to isolating and identifying radioactive isotopes leading to the recognition that the radiation was generated at the atomic level.[23]

Röntgen was awarded the 1901 Nobel Prize in Physics "in recognition of the extraordinary services he has rendered by the discovery of the remarkable rays subsequently named after him."[24] Shy in public speaking, he declined to give a Nobel lecture.[19]: 39  Like Marie and Pierre Curie, he refused to take out patents related to his discovery of X-rays, as he wanted society as a whole to benefit from practical applications of the phenomenon.

Personal life

First X-ray by Röntgen of his wife Anna Bertha Ludwig's hand.

Röntgen was married to Anna Bertha Ludwig[25] for 47 years until her death in 1919 at the age of 80. In 1866, they met in Zurich at Anna's father's café, Zum Grünen Glas. They became engaged in 1869 and wed in Apeldoorn, Netherlands, on 7 July 1872; the delay was due to Anna being six years Wilhelm's senior and his father disapproving of her age or humble background. Their marriage began with financial difficulties as family support from Röntgen had ceased. They raised one child, Josephine Bertha Ludwig, whom they adopted as a 6-year-old after her father, Anna's only brother, died in 1887.[26]

Röntgen was a member of the Dutch Reformed Church.[27]

Recognition

Awards

Year Organization Award Citation Ref.
1896 United Kingdom of Great Britain and Ireland Royal Society Rumford Medal[b] "For their investigations of the phenomena produced outside a highly exhausted tube through which an electrical discharge is taking place." [28]
1896 Kingdom of Italy Accademia dei XL Matteucci Medal[c] [29]
1898 United States Franklin Institute Elliott Cresson Medal "For the discovery of X-rays." [30]
1901 Sweden Royal Swedish Academy of Sciences Nobel Prize in Physics "In recognition of the extraordinary services he has rendered by the discovery of the remarkable rays subsequently named after him." [24]

Memberships

Year Organization Type Ref.
1897 United States American Philosophical Society International Member [31]
1907 Netherlands Royal Netherlands Academy of Arts and Sciences Foreign Member [32]

Orders

Year Head of state Order Ref.
1911 German Empire Wilhelm II Pour le Mérite [33]

Commemoration

Wall art by the house where Röntgen lived from 1863 until 1865 on Schalkwijkstraat in Utrecht. Made by Jackie Sleper in 2005.
Röntgen's marble bust at the Deutsches Museum in Munich.

In November 2004, the IUPAC named element number 111 roentgenium (Rg) in his honor. The IUPAP adopted the name in November 2011.

A collection of Röntgen's papers is held at the National Library of Medicine in Bethesda, Maryland.[34]

Today, in Remscheid-Lennep, 40 kilometres east of Röntgen's birthplace in Düsseldorf, is the Deutsches Röntgen-Museum.[35]

In Würzburg, where Röntgen discovered X-rays, a non-profit organization maintains his laboratory and provides guided tours to the Röntgen Memorial Site.[36]

World Radiography Day is an annual event promoting the role of medical imaging in modern healthcare. It is celebrated on 8 November each year, coinciding with the anniversary of Röntgen's discovery. It was first introduced in 2012 as a joint initiative between the European Society of Radiology, the Radiological Society of North America, and the American College of Radiology.

As of 2023, 55 stamps from 40 countries have been issued commemorating Röntgen as the discoverer of X-rays.[37][38]

Röntgen Peak in Antarctica is named after Wilhelm Röntgen.[39]

Minor planet 6401 Roentgen is named after him.[40]

See also

Notes

  1. ^ /ˈrɛntɡən, ˈrʌnt-/ RENT-guhn, RUHNT-;[3] German: [ˈvɪlhɛlm ˈʁœntɡən] ⓘ
  2. ^ Awarded jointly with Philipp Lenard.
  3. ^ Awarded jointly with Philipp Lenard.

References

  1. ^ a b c d e "Physics Tree - Wilhelm Röntgen". academictree.org. Retrieved 4 September 2025.
  2. ^ "Wilhelm Röntgen". Mathematics Genealogy Project. North Dakota State University. Retrieved 29 May 2025.
  3. ^ "Röntgen". Dictionary.com. Archived from the original on 20 April 2024. Retrieved 25 May 2025.
  4. ^ "Wilhelm Röntgen, ontdekker röntgenstraling". historiek.net (in Dutch). 31 October 2010.
  5. ^ Novelize, Robert. Squire's Fundamentals of Radiology. Harvard University Press. 5th ed. 1997. ISBN 0-674-83339-2 p. 1.
  6. ^ a b Stoddart, Charlotte (1 March 2022). "Structural biology: How proteins got their close-up". Knowable Magazine. doi:10.1146/knowable-022822-1. Retrieved 25 March 2022.
  7. ^ "Wilhelm Conrad Röntgen – Facts". Nobel Foundation. Archived from the original on 7 October 2025. Retrieved 19 May 2025.
  8. ^ a b c "Featured History: Wilhelm Röntgen". rad.washington.edu. Archived from the original on 7 October 2022. Retrieved 2 September 2019.
  9. ^ a b Segovia-Buendía, Cristina (22 July 2020). "Röntgens Wurzeln im Bergischen". Lüttringhauser Anzeiger (in German).
  10. ^ Rosenbusch, Gerd. Wilhelm Conrad Röntgen: The Birth of Radiology. p. 10.
  11. ^ "Wilhelm Conrad Röntgen – Biographical". NobelPrize.org.
  12. ^ Trevert, Edward (1988). Something About X-Rays for Everybody. Madison, Wisconsin: Medical Physics Publishing Corporation. p. 4. ISBN 0-944838-05-7.
  13. ^ a b c Chisholm, Hugh, ed. (1911). "Röntgen, Wilhelm Konrad" . Encyclopædia Britannica. Vol. 23 (11th ed.). Cambridge University Press. p. 694.
  14. ^ a b Nitske, Robert W., The Life of W. C. Röntgen, Discoverer of the X-Ray, University of Arizona Press, 1971.
  15. ^ a b Glasser, Otto (1933). Wilhelm Conrad Röntgen and the Early History of the Roentgen Rays. London: John Bale, Sons and Danielsson, Ltd. p. 305. OCLC 220696336.
  16. ^ "Wilhelm Conrad Röntgen was born on March 27, 1845".
  17. ^ Treutwein, Marius (October 2023). "Röntgen's last will". Physics and Imaging in Radiation Oncology. 28 100503. doi:10.1016/j.phro.2023.100503. ISSN 2405-6316.
  18. ^ Agar, Jon (2012). Science in the Twentieth Century and Beyond. Cambridge: Polity Press. p. 18. ISBN 978-0-7456-3469-2.
  19. ^ a b Pais, Abraham (2002). Inward bound: of matter and forces in the physical world (Reprint ed.). Oxford: Clarendon Press [u.a.] ISBN 978-0-19-851997-3.
  20. ^ "Röntgen´s X-rays". German Patent and Trade Mark Office. Retrieved 22 July 2025.
  21. ^ Landwehr, Gottfried (1997). Hasse, A (ed.). Röntgen centennial: X-rays in Natural and Life Sciences. Singapore: World Scientific. pp. 7–8. ISBN 981-02-3085-0.
  22. ^ Wilhelm Röntgen, "Ueber eine neue Art von Strahlen. Vorläufige Mitteilung", in: Aus den Sitzungsberichten der Würzburger Physik.-medic. Gesellschaft Würzburg, pp. 137–147, 1895; Wilhelm Röntgen, "Eine neue Art von Strahlen. 2. Mitteilung", in: Aus den Sitzungsberichten der Würzburger Physik.-medic. Gesellschaft Würzburg, pp. 11–17, 1896; Wilhelm Röntgen, "Weitere Beobachtungen über die Eigenschaften der X-Strahlen", in: Mathematische und Naturwissenschaftliche Mitteilungen aus den Sitzungsberichten der Königlich Preußischen Akademie der Wissenschaften zu Berlin, pp. 392–406, 1897.
  23. ^ Tretkoff, Ernie (March 2008). "March 1, 1896: Henri Becquerel Discovers Radioactivity". American Physical Society.
  24. ^ a b "Nobel Prize in Physics 1901". Nobel Foundation. Archived from the original on 17 October 2008. Retrieved 9 October 2008.
  25. ^ Jain, C. "Spouse - source from Wilhelm Conrad Röntgen Biographical". Wilhelm Conrad Röntgen Biographical.
  26. ^ Glasser (1933: 63)
  27. ^ Knecht-van Eekelen, Annemarie de (2019). Wilhelm Conrad Röntgen: The Birth of Radiology. Springer. p. 4. ISBN 978-3-319-97661-7. Wilhelm Conrad and his father were members of the Dutch Reformed Church, the mainstream Protestant.
  28. ^ "Rumford Medal". royalsociety.org. Retrieved 19 June 2024.
  29. ^ "Medaglie". www.accademiaxl.it (in Italian). Retrieved 4 November 2025.
  30. ^ "Wilhelm Conrad Röntgen". Franklin Institute. Archived from the original on 1 October 2025. Retrieved 14 November 2025.
  31. ^ "APS Member History". search.amphilsoc.org. Archived from the original on 20 January 2025. Retrieved 22 February 2024.
  32. ^ "W.C. Röntgen (1845 - 1923)". www.dwc.knaw.nl. Archived from the original on 1 October 2025. Retrieved 15 July 2015.
  33. ^ "Wilhelm Conrad Röntgen". www.orden-pourlemerite.de (in German). Retrieved 2 December 2025.
  34. ^ "Fundamental contributions to the X-ray: the three original communications on a new kind of ray / Wilhelm Conrad Röentgen, 1972". National Library of Medicine.
  35. ^ Deutsches Röntgen-Museum at roentgen-museum.de
  36. ^ Röntgen Memorial Site at wilhelmconradroentgen.de
  37. ^ Guzei, Ilia (2023). "Wilhelm Conrad Röntgen - on international postage stamps". Retrieved 16 August 2024.
  38. ^ Munk, Peter L.; Peh, Wilfred C.G. (2023). "Rontgen and the Discovery of X rays on stamps". The Canadian Philatelist. 74 (1): 14–19.
  39. ^ Röntgen Peak. SCAR Composite Antarctic Gazetteer
  40. ^ "(6401) Roentgen". (6401) Roentgen In: Dictionary of Minor Planet Names. Springer. 2003. p. 530. doi:10.1007/978-3-540-29925-7_5844. ISBN 978-3-540-29925-7.
Wikimedia Commons has media related to Wilhelm Conrad Röntgen.
Wikiquote has quotations related to Wilhelm Röntgen.
English Wikisource has original works by or about:
Wilhelm Conrad Röntgen
  • Wilhelm Röntgen on Nobelprize.org
  • Annotated bibliography for Wilhelm Röntgen from the Alsos Digital Library Archived 3 August 2017 at the Wayback Machine
  • Wilhelm Conrad Röntgen Biography
  • The Cathode Ray Tube site
  • First X-ray Photogram
  • The American Roentgen Ray Society
  • Deutsches Röntgen-Museum (German Röntgen Museum, Remscheid-Lennep)
  • Works by or about Wilhelm Röntgen at the Internet Archive
  • Works by Wilhelm Conrad Röntgen at LibriVox (public domain audiobooks)
  • Röntgen Rays: Memoirs by Röntgen, Stokes, and J.J. Thomson (circa 1899)
  • The New Marvel in Photography, an article on and interview with Röntgen, in McClure's magazine, Vol. 6, No. 5, April 1896, from Project Gutenberg
  • Röntgen's 1895 article, on line and analyzed on BibNum Archived 9 May 2016 at the Wayback Machine [click 'à télécharger' for English analysis]
  • Works by Wilhelm Röntgen at Open Library
  • Newspaper clippings about Wilhelm Röntgen in the 20th Century Press Archives of the ZBW
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