Simon Newcomb

Last updated
Simon Newcomb
Simon Newcomb 01.jpg
Newcomb c. 1905
Born(1835-03-12)March 12, 1835
DiedJuly 11, 1909(1909-07-11) (aged 74)
Alma mater Harvard University (BSc, 1858)
Mary Caroline Hassler(m. 1863)
Children4, incl. Dr. Anita Newcomb McGee
Awards Copley Medal (1890)
Bruce Medal (1898)
Scientific career
Fields Astronomy
Academic advisors Benjamin Peirce
Doctoral students Henry Ludwell Moore

Simon Newcomb (March 12, 1835 – July 11, 1909) was a CanadianAmerican astronomer, applied mathematician and autodidactic polymath, who was Professor of Mathematics in the U.S. Navy and at Johns Hopkins. [1]

Canadians citizens of Canada

Canadians are people identified with the country of Canada. This connection may be residential, legal, historical or cultural. For most Canadians, several of these connections exist and are collectively the source of their being Canadian.

Americans Citizens, or natives, of the United States of America

Americans are nationals and citizens of the United States of America. Although nationals and citizens make up the majority of Americans, some dual citizens, expatriates, and permanent residents may also claim American nationality. The United States is home to people of many different ethnic origins. As a result, American culture and law does not equate nationality with race or ethnicity, but with citizenship and permanent allegiance.

Astronomer Scientist who studies celestial bodies

An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, moons, comets, and galaxies – in either observational or theoretical astronomy. Examples of topics or fields astronomers study include planetary science, solar astronomy, the origin or evolution of stars, or the formation of galaxies. Related but distinct subjects like physical cosmology, which studies the Universe as a whole.


Though he had little conventional schooling, he made important contributions to timekeeping as well as other fields in applied mathematics such as economics and statistics in addition to writing a science fiction novel.

Applied mathematics Application of mathematical methods to other fields

Applied mathematics is the application of mathematical methods by different fields such as science, engineering, business, computer science, and industry. Thus, applied mathematics is a combination of mathematical science and specialized knowledge. The term "applied mathematics" also describes the professional specialty in which mathematicians work on practical problems by formulating and studying mathematical models. In the past, practical applications have motivated the development of mathematical theories, which then became the subject of study in pure mathematics where abstract concepts are studied for their own sake. The activity of applied mathematics is thus intimately connected with research in pure mathematics.

Economics Social science that analyzes the production, distribution, and consumption of goods and services

Economics is the social science that studies the production, distribution, and consumption of goods and services.

Statistics Study of the collection, analysis, interpretation, and presentation of data

Statistics is a branch of mathematics working with data collection, organization, analysis, interpretation and presentation. In applying statistics to a scientific, industrial, or social problem, it is conventional to begin with a statistical population or a statistical model to be studied. Populations can be diverse groups of people or objects such as "all people living in a country" or "every atom composing a crystal". Statistics deals with every aspect of data, including the planning of data collection in terms of the design of surveys and experiments. See glossary of probability and statistics.


Early life

Simon Newcomb was born in the town of Wallace, Nova Scotia. His parents were Emily Prince, the daughter of a New Brunswick magistrate, and itinerant school teacher John Burton Newcomb. John moved around teaching in different parts of Canada, particularly in different villages in Nova Scotia and Prince Edward Island. Emily was a daughter of Thomas Prince and Miriam Steeves, making Simon a great-great-grandson of Heinrich Stief, and a not-too-distant cousin of William Henry Steeves, a Canadian Father of Confederation.

Wallace, Nova Scotia rural community in Cumberland County, Nova Scotia, Canada

Wallace is a rural community in Cumberland County, Nova Scotia, Canada.

Nova Scotia Province of Canada

Nova Scotia is one of Canada's three Maritime Provinces, and one of the four provinces that form Atlantic Canada. Its provincial capital is Halifax. Nova Scotia is the second-smallest of Canada's ten provinces, with an area of 55,284 square kilometres (21,300 sq mi), including Cape Breton and another 3,800 coastal islands. As of 2016, the population was 923,598. Nova Scotia is Canada's second-most-densely populated province, after Prince Edward Island, with 17.4 inhabitants per square kilometre (45/sq mi).

Prince Edward Island Province of Canada

Prince Edward Island is a province of Canada consisting of the Atlantic island of the same name along with several much smaller islands nearby. PEI is one of the three Maritime Provinces. It is the smallest province of Canada in both land area and population, but it is the most densely populated. Part of the traditional lands of the Mi'kmaq, it became a British colony in the 1700s and was federated into Canada as a province in 1873. Its capital is Charlottetown. According to the 2016 census, the province of PEI has 142,907 residents.

Newcomb seems to have had little conventional schooling other than from his father and from a short apprenticeship to Dr. Foshay, a charlatan herbalist, in New Brunswick in 1851. Nevertheless, his father provided him with an excellent foundation for his future studies. Newcomb's apprenticeship with Dr. Foshay occurred when he was 16-years-old. They entered an agreement that Newcomb would serve a five-year apprenticeship during which time Foshay would train him in using herbs to treat illnesses. For two years he was an apprentice but became increasingly unhappy and disillusioned with his apprenticeship and about Foshay's unscientific approach, realizing that the man was a charlatan. He made the decision to walk out on Foshay and break their agreement. He walked the 120 miles (190 km) to the port of Calais in Maine where he met the captain of a ship who agreed to take him to Salem, Massachusetts so that he could join his father. [2] In about 1854, he joined his father in Salem (John Newcomb had moved earlier to the United States), and the two journeyed together to Maryland.

Salem, Massachusetts City in Massachusetts, United States

Salem is a historic coastal city in Essex County, Massachusetts, located in the North Shore region. It was one of the most significant seaports in early American history.

After arriving in Maryland, Newcomb taught for two years from 1854 to 1856; for the first year in a country school in Massey's Cross Roads, Kent County, Maryland, then for a year at a school not far south in Sudlersville in Queen Anne's County, Maryland. In his spare time he studied a variety of subjects such as political economy and religion, but his deepest studies were made in mathematics and astronomy. In particular he read Newton's Principia at this time. In 1856 he took up a position as a private tutor close to Washington and he often travelled to that city to study mathematics in the libraries there. He was able to borrow a copy of Bowditch's translation of Laplace's Traité de mécanique céleste from the library of the Smithsonian Institution but found the mathematics beyond him. [3]

Kent County, Maryland County in the United States

Kent County is a county located in the U.S. state of Maryland. As of the 2010 census, its population was 20,197, making it the least populous county in Maryland. Its county seat is Chestertown. The county was named for the county of Kent in England. The county is located on Maryland's Eastern Shore.

Sudlersville, Maryland Town in Maryland, United States

Sudlersville is a town in the far northeastern corner of Queen Anne's County, Maryland, United States. The ZIP code is 21668 and the area code is 410. The population was 497 at the 2010 census. It is perhaps best known as the hometown of Baseball Hall of Fame slugger Jimmie Foxx. Other famous residents include astronomer and mathematician Simon Newcomb.

Queen Annes County, Maryland County in the United States

Queen Anne's County is a county located in the U.S. state of Maryland. As of the 2010 census, the population was 47,798. Its county seat and most populous municipality is Centreville. The census-designated place of Stevensville is the county's most populous place. The county is named for Queen Anne of Great Britain who reigned when the county was established in 1706.

Newcomb studied mathematics and physics privately and supported himself by teaching before becoming a human computer (a functionary in charge of calculations) at the Nautical Almanac Office in Cambridge, Massachusetts in 1857. At around the same time, he enrolled at the Lawrence Scientific School of Harvard University, graduating BSc in 1858. [3]

Mathematics Field of study concerning quantity, patterns and change

Mathematics includes the study of such topics as quantity, structure, space, and change. It has no generally accepted definition.

Physics Study of the fundamental properties of matter and energy

Physics is the natural science that studies matter, its motion and behavior through space and time, and that studies the related entities of energy and force. Physics is one of the most fundamental scientific disciplines, and its main goal is to understand how the universe behaves.

Human computer occupation

The term "computer", in use from the early 17th century, meant "one who computes": a person performing mathematical calculations, before electronic computers became commercially available. "The human computer is supposed to be following fixed rules; they have no authority to deviate from them in any detail." Teams of people were frequently used to undertake long and often tedious calculations; the work was divided so that this could be done in parallel. Frequently, the same calculations were performed independently by separate teams to check the correctness of the results.

Peirce family

Newcomb studied mathematics under Benjamin Peirce and the impecunious Newcomb was often a welcome guest at the Peirce home. [4] However, he later was said to develop a dislike of Peirce's son, Charles Sanders Peirce and has been accused of a "successful destruction" of C. S. Peirce's career. [5] In particular, Daniel Coit Gilman, president of Johns Hopkins University, is alleged to have been on the point of awarding tenure to C. S. Peirce, before Newcomb intervened behind the scenes to dissuade him. [6] About 20 years later, Newcomb allegedly influenced the Carnegie Institution Trustees, to prevent C. S. Peirce's last chance to publish his life's work, through a denial of a Carnegie grant to Peirce, even though Andrew Carnegie himself, Theodore Roosevelt, William James and others, wrote to support it. [7]

Career in astronomy

In the prelude to the American Civil War, many US Navy staff of Confederate sympathies left the service and, in 1861, Newcomb took advantage of one of the ensuing vacancies to become professor of mathematics and astronomer at the United States Naval Observatory, Washington D.C.. Newcomb set to work on the measurement of the position of the planets as an aid to navigation, becoming increasingly interested in theories of planetary motion. [3]

By the time Newcomb visited Paris, France in 1870, he was already aware that the table of lunar positions calculated by Peter Andreas Hansen was in error. While in Paris, he realised that, in addition to the data from 1750 to 1838 that Hansen had used, there was further data stretching as far back as 1672. His visit allowed little serenity for analysis as he witnessed the defeat of French emperor Napoleon III in the Franco-Prussian War and the coup that ended the Second French Empire. Newcomb managed to escape from the city during the ensuing rioting that led up to the formation of the Paris Commune and which engulfed the Paris Observatory. Newcomb was able to use the "new" data to revise Hansen's tables. [3]

He was offered the post of director of the Harvard College Observatory in 1875 but declined, having by now settled that his interests lay in mathematics rather than observation. [3]

Director of the Nautical Almanac Office

In 1877 he became director of the Nautical Almanac Office where, ably assisted by George William Hill, he embarked on a program of recalculation of all the major astronomical constants. Despite fulfilling a further demanding role as professor of mathematics and astronomy at Johns Hopkins University from 1884, he conceived with A. M. W. Downing a plan to resolve much international confusion on the subject. By the time he attended a standardisation conference in Paris, France, in May 1896, the international consensus was that all ephemerides should be based on Newcomb's calculations—Newcomb's Tables of the Sun. A further conference as late as 1950 confirmed Newcomb's constants as the international standard. [3]

Personal life

Grave of Simon Newcomb in Arlington National Cemetery Newcomb Simon.jpg
Grave of Simon Newcomb in Arlington National Cemetery

Newcomb married Mary Caroline Hassler on August 4, 1863 and had four daughters with her.[ citation needed ] Mary Caroline Hassler's father was United States Navy Surgeon Dr. Charles Augustus Hassler and her grandfather was Ferdinand Hassler, the first Superintendent of the Coast Survey.[ citation needed ] Newcomb died in Washington, DC of bladder cancer and was buried with military honors in Arlington National Cemetery with President William Howard Taft in attendance. [3]

Newcomb's daughter Anita Newcomb McGee was an MD and founder of the Army Nurse Corps. She received the Spanish War Service Medal for her services during the Spanish–American War. For her work in Japan she was awarded the Japanese Imperial Order of the Precious Crown, The Japanese Red Cross decoration and two Russo–Japanese War medals from the Japanese government. She is buried next to him with full military honors. [8]

Newcomb's daughter Anna Josepha studied at the Art Students' League in New York. [9] She was active in the suffrage movement. In 1912, she organized the first Cornwall meeting in support of voting rights for women. [9] Josepha Newcomb married Assistant US Attorney General Edward Baldwin Whitney, who was the son of Professor William Dwight Whitney and the grandson of US Senator and Connecticut Governor Roger Sherman Baldwin. He was also the grandfather of mathematician and Professor Hassler Whitney. [10]


Speed of light

In 1878, Newcomb had started planning for a new and precise measurement of the speed of light that was needed to account for exact values of many astronomical constants. He had already started developing a refinement of the method of Léon Foucault when he received a letter from the young naval officer and physicist Albert Abraham Michelson who was also planning such a measurement. Thus began a long collaboration and friendship. In 1880, Michelson assisted at Newcomb's initial measurement with instruments located at Fort Myer and the United States Naval Observatory, then situated on the Potomac River. However, Michelson had left to start his own project by the time of the second set of measurements between the observatory and the Washington Monument. Though Michelson published his first measurement in 1880, Newcomb's measurement was substantially different. In 1883, Michelson revised his measurement to a value closer to Newcomb's. [3]

Benford's law

In 1881, Newcomb discovered the statistical principle now known as Benford's law, when he observed that the earlier pages of logarithm books, used at that time to carry out logarithmic calculations, were far more worn than the later pages. This led him to formulate the principle that, in any list of numbers taken from an arbitrary set of data, more numbers will tend to begin with "1" than with any other digit. [11]

Chandler wobble

In 1891, within months of Seth Carlo Chandler's discovery of the 14-month variation of latitude, now referred to as the Chandler wobble, Newcomb explained the apparent conflict between the observed motion and predicted period of the wobble. The theory was based on a perfectly rigid body, but Earth is slightly elastic. Newcomb used the variation of latitude observations to estimate the elasticity of Earth, finding it to be slightly more rigid than steel. [12]

Other work

Newcomb was an autodidact and polymath. He wrote on economics and his Principles of political economy (1885) was described by John Maynard Keynes as "one of those original works which a fresh scientific mind, not perverted by having read too much of the orthodox stuff, is able to produce from time to time in a half-formed subject like economics." He was credited by Irving Fisher with the first-known enunciation of the equation of exchange between money and goods used in the quantity theory of money. [13] He spoke French, German, Italian and Swedish; was an active mountaineer; widely read; and authored a number of popular science books and a science fiction novel, His Wisdom the Defender (1900). [3]

On the state of astronomy

In 1888 Simon Newcomb wrote: "We are probably nearing the limit of all we can know about astronomy."

In 1900, he published Elements of Astronomy, published by the American Book Company.

By 1903, however, his view had changed. In an article in Science he wrote: "What lies before us is an illimitable field, the existence of which was scarcely suspected ten years ago, the exploration of which may well absorb the activities of our physical laboratories, and of the great mass of our astronomical observers and investigators for as many generations as were required to bring electrical science to its present state." [14]

On the impossibility of a flying machine

Newcomb is famously quoted as having believed it impossible to build a "flying machine". He begins an article titled "Is the Airship Possible?" with the remark, "That depends, first of all, on whether we are to make the requisite scientific discoveries." He ends with the remark "the construction of an aerial vehicle ... which could carry even a single man from place-to-place at pleasure requires the discovery of some new metal or some new force." [15]

In the October 22, 1903, issue of The Independent, Newcomb made the well-known remark that "May not our mechanicians . . . be ultimately forced to admit that aerial flight is one of the great class of problems with which man can never cope, and give up all attempts to grapple with it?", [16] [17] completed by the motivation that even if a man flew he could not stop. "Once he slackens his speed, down he begins to fall. Once he stops, he falls as a dead mass." He had no concept of an airfoil. His "aeroplane" was an inclined "thin flat board". He therefore concluded that it could never carry the weight of a man.

Newcomb was specifically critical of the work of Samuel Pierpont Langley, who claimed that he could build a flying machine powered by a steam engine and whose initial efforts at flight were public failures. [18] In 1903, however, Newcomb was also saying, "Quite likely the 20th century is destined to see the natural forces which will enable us to fly from continent to continent with a speed far exceeding that of a bird. But when we inquire whether aerial flight is possible in the present state of our knowledge; whether, with such materials as we possess, a combination of steel, cloth and wire can be made which, moved by the power of electricity or steam, shall form a successful flying machine, the outlook may be altogether different." [19]

Newcomb was clearly unaware of the Wright Brothers' efforts whose work was done in relative obscurity and apparently unaware of the internal combustion engine's better power-to-weight ratio. When he heard about the Wrights' flight in 1908 he was quick to accept it. [20] Newcomb favored the development of rotating wing (helicopters) and airships that would float in the air (blimps). Within a few decades, Zeppelins regularly transported passengers between Europe and the United States, and the Graf Zeppelin circumnavigated the Earth. [21]

Psychical research

Newcomb was the first president of the American Society for Psychical Research. [22] Although skeptical of extrasensory perception and alleged paranormal phenomena he believed the subject was worthy of investigation. By 1889 his investigations were negative and his skepticism increased. Biographer Albert E. Moyer has noted that Newcomb "convinced and hoped to convince others that, on methodological grounds, psychical research was a scientific dead end." [23]

Awards and honours



A number of astronomical, physical, and mathematical papers written between 1882 and 1912 are mentioned in "Astronomical Papers Prepared For The Use Of The American Ephemeris And Nautical Almanac". U.S. Naval Observatory. The Nautical Almanac Office. 2008-08-12. Retrieved 2009-02-24.

See also

Related Research Articles

Albert A. Michelson American physicist

Albert Abraham Michelson FFRS HFRSE was an American physicist known for his work on measuring the speed of light and especially for the Michelson–Morley experiment. In 1907 he received the Nobel Prize in Physics, becoming the first American to win the Nobel Prize in a science.

Peter Andreas Hansen German astronomer

Peter Andreas Hansen was a Danish German astronomer.

James Glaisher British meteorologist and aeronaut

James Glaisher FRS was an English meteorologist, aeronaut and astronomer.

Hassler Whitney American mathematician

Hassler Whitney was an American mathematician. He was one of the founders of singularity theory, and did foundational work in manifolds, embeddings, immersions, characteristic classes, and geometric integration theory.

Martin Ryle English radio astronomer

Sir Martin Ryle was an English radio astronomer who developed revolutionary radio telescope systems and used them for accurate location and imaging of weak radio sources. In 1946 Ryle and Derek Vonberg were the first people to publish interferometric astronomical measurements at radio wavelengths. With improved equipment, Ryle observed the most distant known galaxies in the universe at that time. He was the first Professor of Radio Astronomy at the University of Cambridge, and founding director of the Mullard Radio Astronomy Observatory. He was Astronomer Royal from 1972 to 1982. Ryle and Antony Hewish shared the Nobel Prize for Physics in 1974, the first Nobel prize awarded in recognition of astronomical research. In the 1970s, Ryle turned the greater part of his attention from astronomy to social and political issues which he considered to be more urgent.

Arthur Matthew Weld Downing FRAS was an Irish mathematician and astronomer. Downing's major contribution to astronomy is in the calculation of the positions and movements of astronomical bodies, as well as being a founder of the British Astronomical Association.

Otto Wilhelm von Struve Russian astronomer

Otto Wilhelm von Struve was a Baltic German astronomer. In Russian, his name is normally given as Otto Vasil'evich Struve. Together with his father, Friedrich Georg Wilhelm von Struve, Otto Wilhelm von Struve is considered a prominent 19th century astronomer who headed the Pulkovo Observatory between 1862 and 1889 and was a leading member of the Russian Academy of Sciences.

William Wallace Campbell American astronomer

William Wallace Campbell was an American astronomer, and director of Lick Observatory from 1901 to 1930. He specialized in spectroscopy.

Seth Carlo Chandler American astronomer

Seth Carlo Chandler, Jr. was an American astronomer.

Benjamin Apthorp Gould American astronomer

Benjamin Apthorp Gould was a pioneering American astronomer. He is noted for creating the Astronomical Journal, discovering the Gould Belt, and for founding of the Argentine National Observatory and the Argentine National Weather Service.

Richard Quintin Twiss was a British astronomer. He is known for his work on the Hanbury-Brown and Twiss effect with Robert Hanbury Brown. It led to the development of the Hanbury Brown-Twiss intensity interferometer in the UK in 1954. Their work appeared to contradict the established beliefs about quantum interference, and he and Brown received the Eddington Medal of the Royal Astronomical Society for it in 1968.

Samuel Alfred Mitchell American astronomer

Samuel Alfred Mitchell was a Canadian-American astronomer who studied solar eclipses and set up a program to use photographic techniques to determine the distance to stars at McCormick Observatory, where he served as the director.

Ormond Stone American astronomer

Ormond Stone, was an American astronomer, mathematician and educator. He was the director of Cincinnati Observatory and subsequently the first director of the McCormick Observatory at the University of Virginia, where he trained a significant number of scientists. He served as the editor of the Annals of Mathematics and towards the end of his life made donations which led to the founding of the Fairfax Public Library System.

Mary Watson Whitney astronomer

Mary Watson Whitney was an American astronomer and for 22 years the head of the Vassar Observatory where 102 scientific papers were published under her guidance.

Richard Hawley Tucker was an American astronomer.

Astronomical Observatory (University of Illinois at Urbana–Champaign)

The University of Illinois Astronomical Observatory, located at 901 S. Mathews Avenue in Urbana, Illinois, on the campus of the University of Illinois at Urbana–Champaign, was built in 1896, and was designed by Charles A. Gunn. It has been listed on the National Register of Historic Places since November 6, 1986, and on December 20, 1989, was designated a National Historic Landmark.

Gerald Maurice Clemence was an American astronomer. Inspired by the life and work of Simon Newcomb, his career paralleled the huge advances in astronomy brought about by the advent of the electronic computer. Clemence did much to revive the prestige of the U.S. Nautical Almanac Office.

Isabel Martin Lewis astronomer

Isabel Martin Lewis was an American astronomer who was the first woman hired by the United States Naval Observatory as assistant astronomer. In 1918, Lewis was elected a member of the American Astronomical Society. She was also a member of the Royal Astronomical Society of Canada and the Astronomical Society of the Pacific.

Sidney Wilcox McCuskey was an American mathematician and astronomer.

John Wainwright Evans was an American solar astronomer born in New York City. He spent much of his career studying the sun and working with optics both of which earned him awards. The Evans Solar Facility at Sacramento Peak was named after him. Evans died in a murder–suicide with his wife in 1999.


  1. John Maynard Keynes (1930). A Treatise on Money. Vol. 1, p. 233
  2. Marsden (1981)
  3. 1 2 3 4 5 6 7 8 9 Newcomb biography.
  4. Brent (1993) p. 288
  5. Brent (1993) p. 128
  6. Brent (1993) pp. 150–153
  7. Brent (1993) pp. 287–289
  8. "National Museum of Health and Medicine (NMHM): American Angels of Mercy: Dr. Anita Newcomb McGee's Pictorial Record of the Russo–Japanese War, 1904: Dr. Anita Newcomb McGee, 1864–1940". Retrieved 2016-09-30.
  9. 1 2 "Josepha Newcomb Whitney". Retrieved 2016-09-30.
  10. Chern, Shiing-Shen (September 1994). "Hassler Whitney (23 March 1907-10 May 1989)". Proceedings of the American Philosophical Society. 138 (3): 464–467. JSTOR   986754.
  11. Newcomb (1881)
  12. Newcomb (1902) p. 116
  13. Fisher (1909).
  14. Newcomb, S. (January 23, 1903), "The Universe as an Organism", Science , (N.S.), 17 (421): 121–129, Bibcode:1903Sci....17..121N, doi:10.1126/science.17.421.121, JSTOR   1631452 . The quote is in the final paragraph, on p. 129.
  15. Newcomb, Simon (September 1901). "Is the Airship Coming?". McClure's Magazine. S. S. McClure, Limited. 17 (5): 432–435.
  16. Galluzzo, John (19 July 2018). When Hull Freezes Over: Historic Winter Tales from the Massachusetts Shore. History Press. ISBN   9781596290990 . Retrieved 19 July 2018 via Google Books.
  17. "The Outlook for the Flying Machine". The Independent. 55 (2864): 2509. October 22, 1903. Retrieved 26 April 2015.
  18. Albert E. Moyer (1992). A scientist's voice in American culture: Simon Newcomb and the rhetoric of scientific method. University of California Press. p. 187.
  19. "What Did Newcomb Say?". The Independent. New York: Independent Corporation. 103 (3738): 374. September 25, 1920.
  20. Anita Newcomb McGee (April 20, 1919). "Simon Newcomb on Flying. He did not take the gasoline engine into account in his writings". New York Times. Retrieved 2011-01-25.
  21. Time magazine: Los Angeles to Lakehurst, 1929-09-09
  22. Campbell, W. W. (1924). Simon Newcomb. Memoirs of the National Academy of Sciences. p. 14
  23. Moyer, Albert E. (1998). Simon Newcomb: Astronomer with an Attitude. Scientific American 279 (4): 88-93.
  24. "Simon Newcomb (1835–1909)". Royal Netherlands Academy of Arts and Sciences. Retrieved 26 July 2015.
  25. Tenn, Joe S. (November 11, 2015), "Simon Newcomb", The Bruce Medalists, retrieved 2017-11-18.

Further reading