Wilhelm Conrad Röntgen (; 27 March 1845 – 10 February 1923), sometimes
transliterated
Transliteration is a type of conversion of a text from one writing system, script to another that involves swapping Letter (alphabet), letters (thus ''wikt:trans-#Prefix, trans-'' + ''wikt:littera#Latin, liter-'') in predictable ways, such as ...
as Roentgen ( ), was a German
physicist
A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate cau ...
who produced and detected
electromagnetic radiation
In physics, electromagnetic radiation (EMR) is a self-propagating wave of the electromagnetic field that carries momentum and radiant energy through space. It encompasses a broad spectrum, classified by frequency or its inverse, wavelength ...
in a
wavelength
In physics and mathematics, wavelength or spatial period of a wave or periodic function is the distance over which the wave's shape repeats.
In other words, it is the distance between consecutive corresponding points of the same ''phase (waves ...
range known as
X-ray
An X-ray (also known in many languages as Röntgen radiation) is a form of high-energy electromagnetic radiation with a wavelength shorter than those of ultraviolet rays and longer than those of gamma rays. Roughly, X-rays have a wavelength ran ...
s. As a result of this discovery, he became the first recipient of the
Nobel Prize in Physics
The Nobel Prize in Physics () is an annual award given by the Royal Swedish Academy of Sciences for those who have made the most outstanding contributions to mankind in the field of physics. It is one of the five Nobel Prizes established by the ...
in 1901.
[Novelize, Robert. ''Squire's Fundamentals of Radiology''. ]Harvard University Press
Harvard University Press (HUP) is an academic publishing house established on January 13, 1913, as a division of Harvard University. It is a member of the Association of University Presses. Its director since 2017 is George Andreou.
The pres ...
. 5th ed. 1997. p. 1.
Biographical history
Education
Röntgen was born in
Lennep on 27 March 1845 to Friedrich Conrad Röntgen, a German merchant and cloth manufacturer, and Charlotte Constanze Frowein.
When he was aged three, his family moved to the
Netherlands
, Terminology of the Low Countries, informally Holland, is a country in Northwestern Europe, with Caribbean Netherlands, overseas territories in the Caribbean. It is the largest of the four constituent countries of the Kingdom of the Nether ...
, where his mother's family lived,
rendering him
stateless.
He attended high school at Utrecht Technical School in
Utrecht
Utrecht ( ; ; ) is the List of cities in the Netherlands by province, fourth-largest city of the Netherlands, as well as the capital and the most populous city of the Provinces of the Netherlands, province of Utrecht (province), Utrecht. The ...
,
Netherlands
, Terminology of the Low Countries, informally Holland, is a country in Northwestern Europe, with Caribbean Netherlands, overseas territories in the Caribbean. It is the largest of the four constituent countries of the Kingdom of the Nether ...
.
He followed courses at the Technical School for almost two years. In 1865, he was unfairly expelled from high school when one of his teachers intercepted a
caricature
A caricature is a rendered image showing the features of its subject in a simplified or exaggerated way through sketching, pencil strokes, or other artistic drawings (compare to: cartoon). Caricatures can be either insulting or complimentary, ...
of one of the teachers, which was drawn by someone else.
Without a high school diploma, Röntgen could only attend university in the Netherlands as a visitor. In 1865, he tried to attend
Utrecht University
Utrecht University (UU; , formerly ''Rijksuniversiteit Utrecht'') is a public university, public research university in Utrecht, Netherlands. Established , it is one of the oldest universities in the Netherlands. In 2023, it had an enrollment of ...
without having the necessary credentials required for a regular student. Upon hearing that he could enter the
Federal Polytechnic Institute in
Zürich
Zurich (; ) is the list of cities in Switzerland, largest city in Switzerland and the capital of the canton of Zurich. It is in north-central Switzerland, at the northwestern tip of Lake Zurich. , the municipality had 448,664 inhabitants. The ...
(today known as the
ETH Zurich
ETH Zurich (; ) is a public university in Zurich, Switzerland. Founded in 1854 with the stated mission to educate engineers and scientists, the university focuses primarily on science, technology, engineering, and mathematics. ETH Zurich ran ...
), he passed the entrance examination and began his studies there as a student of
mechanical engineering
Mechanical engineering is the study of physical machines and mechanism (engineering), mechanisms that may involve force and movement. It is an engineering branch that combines engineering physics and engineering mathematics, mathematics principl ...
.
In 1869, he graduated with a
PhD
A Doctor of Philosophy (PhD, DPhil; or ) is a terminal degree that usually denotes the highest level of academic achievement in a given discipline and is awarded following a course of graduate study and original research. The name of the deg ...
from the
University of Zurich
The University of Zurich (UZH, ) is a public university, public research university in Zurich, Switzerland. It is the largest university in Switzerland, with its 28,000 enrolled students. It was founded in 1833 from the existing colleges of the ...
; once there, he became a favourite student of Professor
August Kundt
August Adolf Eduard Eberhard Kundt (; 18 November 1839 – 21 May 1894) was a German physicist known for developing Kundt's tube, an appartus used to measure the speed of sound in gases and solids.
Early life
Kundt was born in Schwerin, Meckle ...
, whom he followed to the newly founded German
''Kaiser-Wilhelms-Universität'' in
Strasbourg
Strasbourg ( , ; ; ) is the Prefectures in France, prefecture and largest city of the Grand Est Regions of France, region of Geography of France, eastern France, in the historic region of Alsace. It is the prefecture of the Bas-Rhin Departmen ...
.
Career
In 1874, Röntgen became a
lecturer
Lecturer is an academic rank within many universities, though the meaning of the term varies somewhat from country to country. It generally denotes an academic expert who is hired to teach on a full- or part-time basis. They may also conduct re ...
at the University of Strasbourg. In 1875, he became a
professor
Professor (commonly abbreviated as Prof.) is an Academy, academic rank at university, universities and other tertiary education, post-secondary education and research institutions in most countries. Literally, ''professor'' derives from Latin ...
at the
Academy of Agriculture in
Hohenheim,
Württemberg
Württemberg ( ; ) is a historical German territory roughly corresponding to the cultural and linguistic region of Swabia. The main town of the region is Stuttgart.
Together with Baden and Province of Hohenzollern, Hohenzollern, two other histo ...
. In 1876, he returned to Strasbourg as Professor of
Physics
Physics is the scientific study of matter, its Elementary particle, fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge whi ...
, and in 1879, he was appointed to the Chair of Physics at the
University of Giessen
University of Giessen, official name Justus Liebig University Giessen (), is a large public research university in Giessen, Hesse, Germany. It is one of the oldest institutions of higher education in the German-speaking world. It is named afte ...
. In 1888, he acquired German citizenship again after having been stateless for 40 years,
and obtained the Physics Chair at the
University of Würzburg
The Julius Maximilian University of Würzburg (also referred to as the University of Würzburg, in German ''Julius-Maximilians-Universität Würzburg'') is a public research university in Würzburg, Germany. Founded in 1402, it is one of the ol ...
,
and in 1900 at the
University of Munich
The Ludwig Maximilian University of Munich (simply University of Munich, LMU or LMU Munich; ) is a public university, public research university in Munich, Bavaria, Germany. Originally established as the University of Ingolstadt in 1472 by Duke ...
, by special request of the Bavarian government.
Röntgen had family in
Iowa
Iowa ( ) is a U.S. state, state in the upper Midwestern United States, Midwestern region of the United States. It borders the Mississippi River to the east and the Missouri River and Big Sioux River to the west; Wisconsin to the northeast, Ill ...
in the
United States
The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...
and planned to emigrate. He accepted an appointment at
Columbia University
Columbia University in the City of New York, commonly referred to as Columbia University, is a Private university, private Ivy League research university in New York City. Established in 1754 as King's College on the grounds of Trinity Churc ...
in
New York City
New York, often called New York City (NYC), is the most populous city in the United States, located at the southern tip of New York State on one of the world's largest natural harbors. The city comprises five boroughs, each coextensive w ...
and bought transatlantic tickets, before the outbreak of
World War I
World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...
changed his plans. He remained in Munich for the rest of his career.
Discovery of X-rays
During 1895, at his laboratory in the Würzburg Physical Institute of the University of Würzburg, Röntgen was investigating the external effects of passing an
electrical discharge through various types of vacuum tube equipment—apparatuses from
Heinrich Hertz
Heinrich Rudolf Hertz (; ; 22 February 1857 – 1 January 1894) was a German physicist who first conclusively proved the existence of the electromagnetic waves predicted by James Clerk Maxwell's equations of electromagnetism.
Biography
Heinri ...
,
Johann Hittorf,
William Crookes
Sir William Crookes (; 17 June 1832 – 4 April 1919) was an English chemist and physicist who attended the Royal College of Chemistry, now part of Imperial College London, and worked on spectroscopy. He was a pioneer of vacuum tubes, inventing ...
,
Nikola Tesla
Nikola Tesla (;["Tesla"](_blank)
. ''Random House Webster's Unabridged Dictionary''. ; 10 July 1856 – 7 ...
and
Philipp von Lenard[ 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
Cathode rays are streams of electrons observed in vacuum tube, discharge tubes. If an evacuated glass tube is equipped with two electrodes and a voltage is applied, glass behind the positive electrode is observed to glow, due to electrons emitte ...
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. Röntgen knew that the cardboard covering prevented light from escaping, yet he observed that the invisible cathode rays caused a fluorescent
Fluorescence is one of two kinds of photoluminescence, the emission of light by a substance that has absorbed light or other electromagnetic radiation. When exposed to ultraviolet radiation, many substances will glow (fluoresce) with color ...
effect on a small cardboard screen painted with barium platinocyanide when it was placed close to the aluminium
Aluminium (or aluminum in North American English) is a chemical element; it has chemical symbol, symbol Al and atomic number 13. It has a density lower than that of other common metals, about one-third that of steel. Aluminium has ...
window. 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 a Ruhmkorff coil to generate an electrostatic charge. Before setting up the barium platinocyanide screen to test his idea, Röntgen darkened the room to test the opacity of his cardboard cover. As he passed the Ruhmkorff 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 Röntgen 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". 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 new rays came to bear his name in many languages as "Röntgen rays" (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, he took a picture—a radiograph
Radiography is an imaging technique using X-rays, gamma rays, or similar ionizing radiation and non-ionizing radiation to view the internal form of an object. Applications of radiography include medical ("diagnostic" radiography and "therapeu ...
—using X-rays of his wife Anna Bertha's hand. When she saw her skeleton she exclaimed "I have seen my death!" He later took a better picture of his friend Albert von Kölliker's hand at a public lecture.
Röntgen's original paper, "On A New Kind of Rays" (''Ueber eine neue Art von Strahlen''), was published on 28 December 1895. On 5 January 1896, an Austrian newspaper reported Röntgen's discovery of a new type of radiation. Röntgen was awarded an honorary Doctor of Medicine
A Doctor of Medicine (abbreviated MD, from the Latin language, Latin ) is a medical degree, the meaning of which varies between different jurisdictions. In the United States, and some other countries, the ''MD'' denotes a professional degree of ph ...
degree from the University of Würzburg after his discovery. He also received the Rumford Medal of the British Royal Society
The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, re ...
in 1896, jointly with Philipp Lenard
Philipp Eduard Anton von Lenard (; ; 7 June 1862 – 20 May 1947) was a Hungarian-German physicist who received the Nobel Prize in Physics in 1905 "for his work on cathode rays" and the discovery of many of their properties. One of his most im ...
, who had already shown that a portion of the cathode rays could pass through a thin film of a metal such as aluminium. Röntgen published a total of three papers on X-rays between 1895 and 1897. Today, Röntgen is considered the father of diagnostic radiology
Radiology ( ) is the medical specialty that uses medical imaging to diagnose diseases and guide treatment within the bodies of humans and other animals. It began with radiography (which is why its name has a root referring to radiation), but tod ...
, the medical speciality which uses imaging to diagnose disease.
Personal life
Röntgen was married to Anna Bertha Ludwig for 47 years until her death in 1919 at the age of 80. In 1866, they met in Zürich at Anna's father's café, Zum Grünen Glas. They became engaged in 1869 and wed in Apeldoorn
Apeldoorn (; Dutch Low Saxon: ) is a municipality and city in the province of Gelderland in the centre of the Netherlands. The municipality of Apeldoorn, including the villages of Beekbergen, Loenen (Apeldoorn), Loenen, Ugchelen and Hoenderloo ...
, Netherlands
, Terminology of the Low Countries, informally Holland, is a country in Northwestern Europe, with Caribbean Netherlands, overseas territories in the Caribbean. It is the largest of the four constituent countries of the Kingdom of the Nether ...
on 7 July 1872; the delay was due to Anna being six years Wilhelm's senior and his father not approving 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 six-year-old after her father, Anna's only brother, died in 1887.
For ethical reasons, Röntgen did not seek patents for his discoveries, holding the view that they should be publicly available without charge. After receiving his Nobel prize money, Röntgen donated the 50,000 Swedish kronor to research at the University of Würzburg
The Julius Maximilian University of Würzburg (also referred to as the University of Würzburg, in German ''Julius-Maximilians-Universität Würzburg'') is a public research university in Würzburg, Germany. Founded in 1402, it is one of the ol ...
. Although he accepted the honorary degree of Doctor of Medicine, he rejected an offer of lower nobility, or Niederer Adelstitel, denying the preposition von (meaning "of") as a nobiliary particle
A nobiliary particle is a type of onomastic particle used in a surname or family name in many Western cultures to signal the nobility of a family. The particle used varies depending on the country, language and period of time. In some languages, it ...
(i.e., von Röntgen). With the inflation following World War I, Röntgen fell into bankruptcy, spending his final years at his country home at Weilheim, near Munich.[Nitske, Robert W., ''The Life of W. C. Röntgen, Discoverer of the X-Ray'', University of Arizona Press, 1971.] Röntgen died on 10 February 1923 from carcinoma
Carcinoma is a malignancy that develops from epithelial cells. Specifically, a carcinoma is a cancer that begins in a tissue that lines the inner or outer surfaces of the body, and that arises from cells originating in the endodermal, mesoder ...
of the intestine, also known as colorectal cancer
Colorectal cancer (CRC), also known as bowel cancer, colon cancer, or rectal cancer, is the development of cancer from the Colon (anatomy), colon or rectum (parts of the large intestine). Signs and symptoms may include Lower gastrointestinal ...
. In keeping with his will, his personal and scientific correspondence, with few exceptions, were destroyed upon his death.[ He was a member of the ]Dutch Reformed Church
The Dutch Reformed Church (, , abbreviated NHK ) was the largest Christian denomination in the Netherlands from the onset of the Protestant Reformation in the 16th century until 1930. It was the traditional denomination of the Dutch royal famil ...
.
Awards and honors
*1896: Rumford Medal of the Royal Society
The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, re ...
*1896: Matteucci Medal
The Matteucci Medal is an Italian award for physicists, named after Carlo Matteucci from Forlì. It was established to award physicists for their fundamental contributions. Under an Italian Royal Decree dated July 10, 1870, the Italian Society ...
of the Accademia nazionale delle scienze
*1897: Elliott Cresson Medal
The Elliott Cresson Medal, also known as the Elliott Cresson Gold Medal, was the highest award given by the Franklin Institute. The award was established by Elliott Cresson, life member of the Franklin Institute, with $1,000 granted in 1848. Th ...
of the Franklin Institute
The Franklin Institute is a science museum and a center of science education and research in Philadelphia, Pennsylvania. It is named after the American scientist and wikt:statesman, statesman Benjamin Franklin. It houses the Benjamin Franklin ...
*1900: Barnard Medal for Meritorious Service to Science
The Barnard Medal for Meritorious Service to Science was established in 1889 by the will of Columbia University president Frederick A. P. Barnard, and has been awarded by Columbia University, based on recommendations by the National Academy of S ...
of Columbia University
Columbia University in the City of New York, commonly referred to as Columbia University, is a Private university, private Ivy League research university in New York City. Established in 1754 as King's College on the grounds of Trinity Churc ...
*1901: Nobel Prize in Physics
The Nobel Prize in Physics () is an annual award given by the Royal Swedish Academy of Sciences for those who have made the most outstanding contributions to mankind in the field of physics. It is one of the five Nobel Prizes established by the ...
for the discovery of X-ray
An X-ray (also known in many languages as Röntgen radiation) is a form of high-energy electromagnetic radiation with a wavelength shorter than those of ultraviolet rays and longer than those of gamma rays. Roughly, X-rays have a wavelength ran ...
s
In 1901, Röntgen was awarded the first Nobel Prize in Physics
The Nobel Prize in Physics () is an annual award given by the Royal Swedish Academy of Sciences for those who have made the most outstanding contributions to mankind in the field of physics. It is one of the five Nobel Prizes established by the ...
. The award was officially "in recognition of the extraordinary services he has rendered by the discovery of the remarkable rays subsequently named after him". Shy in public speaking, he declined to give a Nobel lecture.[ Röntgen donated the 50,000 Swedish krona reward from his Nobel Prize to research at his university, the ]University of Würzburg
The Julius Maximilian University of Würzburg (also referred to as the University of Würzburg, in German ''Julius-Maximilians-Universität Würzburg'') is a public research university in Würzburg, Germany. Founded in 1402, it is one of the ol ...
. Like Marie and Pierre Curie
Pierre Curie ( ; ; 15 May 1859 – 19 April 1906) was a French physicist, Radiochemistry, radiochemist, and a pioneer in crystallography, magnetism, piezoelectricity, and radioactivity. He shared the 1903 Nobel Prize in Physics with his wife, ...
, Röntgen 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. Röntgen was also awarded Barnard Medal for Meritorious Service to Science
The Barnard Medal for Meritorious Service to Science was established in 1889 by the will of Columbia University president Frederick A. P. Barnard, and has been awarded by Columbia University, based on recommendations by the National Academy of S ...
in 1900.
In November 2004, IUPAC
The International Union of Pure and Applied Chemistry (IUPAC ) is an international federation of National Adhering Organizations working for the advancement of the chemical sciences, especially by developing nomenclature and terminology. It is ...
named element number 111 roentgenium (Rg) in his honor. IUPAP adopted the name in November 2011.
He was elected an International Member of the American Philosophical Society
The American Philosophical Society (APS) is an American scholarly organization and learned society founded in 1743 in Philadelphia that promotes knowledge in the humanities and natural sciences through research, professional meetings, publicat ...
in 1897. In 1907, he became a foreign member of the Royal Netherlands Academy of Arts and Sciences
The Royal Netherlands Academy of Arts and Sciences (, KNAW) is an organization dedicated to the advancement of science and literature in the Netherlands. The academy is housed in the Trippenhuis in Amsterdam.
In addition to various advisory a ...
.
Legacy
A collection of his papers is held at the National Library of Medicine in Bethesda, Maryland
Bethesda () is an unincorporated, census-designated place in southern Montgomery County, Maryland, United States. Located just northwest of Washington, D.C., it is a major business and government center of the Washington metropolitan region ...
.
Today, in Remscheid-Lennep, 40 kilometres east of Röntgen's birthplace in Düsseldorf
Düsseldorf is the capital city of North Rhine-Westphalia, the most populous state of Germany. It is the second-largest city in the state after Cologne and the List of cities in Germany with more than 100,000 inhabitants, seventh-largest city ...
, is the Deutsches Röntgen-Museum.
In Würzburg
Würzburg (; Main-Franconian: ) is, after Nuremberg and Fürth, the Franconia#Towns and cities, third-largest city in Franconia located in the north of Bavaria. Würzburg is the administrative seat of the Regierungsbezirk Lower Franconia. It sp ...
, where he discovered X-rays, a non-profit organization maintains his laboratory and provides guided tours to the Röntgen Memorial Site.
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 the 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.
Röntgen Peak in Antarctica
Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean (also known as the Antarctic Ocean), it contains the geographic South Pole. ...
is named after Wilhelm Röntgen.
Minor planet 6401 Roentgen is named after him.
See also
* German inventors and discoverers
* Röntgen Memorial Site
* Ivan Puluj
References
External links
*
Annotated bibliography for Wilhelm Röntgen from the Alsos Digital Library
The American Roentgen Ray Society
Deutsches Röntgen-Museum
(German Röntgen Museum, Remscheid
Remscheid () is a city in North Rhine-Westphalia, Germany. It is, after Wuppertal and Solingen, the third-largest municipality in Bergisches Land, being located on the northern edge of the region, on the south side of the Ruhr area.
Remscheid ha ...
-Lennep)
*
*
* 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
''McClure's'' or ''McClure's Magazine'' (1893–1929) was an American illustrated monthly periodical popular at the turn of the 20th century. The magazine is credited with having started the tradition of muckraking journalism (investigative journ ...
magazine, Vol. 6, No. 5, April 1896, from Project Gutenberg
Project Gutenberg (PG) is a volunteer effort to digitize and archive cultural works, as well as to "encourage the creation and distribution of eBooks."
It was founded in 1971 by American writer Michael S. Hart and is the oldest digital li ...
* Röntgen's 1895 article, on line and analyzed on
BibNum
' lick 'à télécharger' for English analysis/small>
*
*
{{DEFAULTSORT:Rontgen, Wilhelm
1845 births
1923 deaths
20th-century German physicists
People from Remscheid
ETH Zurich alumni
Experimental physicists
German Nobel laureates
German people of Dutch descent
Members of the Royal Netherlands Academy of Arts and Sciences
Nobel laureates in Physics
Particle physicists
People from Apeldoorn
People from the Rhine Province
People associated with the University of Zurich
Projectional radiography
Recipients of the Pour le Mérite (civil class)
Science teachers
University of Zurich alumni
Academic staff of the University of Zurich
Academic staff of the University of Giessen
Academic staff of the Ludwig Maximilian University of Munich
Academic staff of the University of Strasbourg
Academic staff of the University of Würzburg
Utrecht University alumni
X-ray pioneers
Engineers from North Rhine-Westphalia
German mechanical engineers
Recipients of the Matteucci Medal
German Calvinist and Reformed Christians
Members of the Dutch Reformed Church
International members of the American Philosophical Society