Saturday, 14 November 2026

The Student's t Distribution....History and Etymology of Math Terms

   Student's t The story of the name for this statistical distribution and test is almost legend, and some version of the tale is remembered by Intro Stats students long after they forgot the purpose of the t-test. A recent dialogue between Randy Schwartz and James A Landau on the Historia Matematica discussion group gives both one of the folk versions, and a brief history.

Randy Schwartz writes "the distribution now known as 'Student's t distribution' was first discussed in print in a paper by Willam S Gosset in the journal Biometrika in 1908, published under the pseudonym 'Student.' The paper solved a problem from the Guinness Brewery concerning how large a sample of people should be used in its tastings of beer. Apparently Gosset was embarrassed to be working on a problem stemming from the liquor industry, thus the pseudonym."
James Landau responds "The story of 'Student' has been told so many times that it has become folklore, and like all folklore variant versions exist until it is difficult to determine which is the original. The variant you tell is one I have not encountered before.
Gosset was an employee of Guinness Brewery (a brewmaster, I believe) who went to study statistics under Karl Pearson. Gosset eventually discovered a result that he published in Biometrika under the pen-name of 'Student.' Why did he choose to use a pseudonym? Here is where the folklore kicks in. The most common story is that Guinness wanted to keep it secret that they were using statistics in their business, and ordered Gosset not to reveal his identity.


In any event, Gosset published all his statistical works as "Student", even though his identity became well known. Why he continued to use the pseudonym is not part of the folklore, and I have never heard a plausible story. Perhaps it is because he became famous as 'Student' and did not want to have to re-establish his professional reputation under his real name. Perhaps he liked the notoriety."
OK, now we know why he used "Student", but why t?

About a year after I wrote the last question in the paragraph above, I picked up a copy of a wonderful book,The Lady Tasting Tea by David Salsburg, and found the answer in a footnote on page 30. He writes "Gosset used the letter "z" to indicate this ratio. Some years later, writers of textbooks began referring to normally distributed variables with the letter "z", and they began using the letter "t" for "Student's ratio".

While looking up some data on the Data and Story Library site, I came across a little historical note that should be included here also:

W.S. Gosset (1876-1937) was employed by the Guniess Brewing Company of Dublin. Sample sizes available for experimentation in brewing were necessarily small, and Gosset knew that a correct way of dealing with small samples was needed. He consulted Karl Pearson (1857-1936) of Universiy College in London about the problem. Pearson told him the current state of knowledge was unsatisfactory. The following year Gosset undertook a course of study under Pearson. An outcome of his study was the publication in 1908 of Gosset's paper on "The Probable Error of a Mean," which introduced a form of what later became known as Student's t-distribution. Gosset's paper was published under the pseudonym "Student." The modern form of Student's t-distribution was derived by R.A. Fisher and first published in 1925.

The t-distribution is a family of curves that discribe the pattern of possible errors when the average of a sample, , is used to estimate the mean of the population, m, from which the sample is taken if the underlying population is normally distributed. The distribution for every different sample size is slightly different, becoming more normal as the size of the sample gets larger. The distribution is given by the function . Think of repeatedly drawning samples of size n from a normal distribution with a mean of m and a standard deviation of s. After each sample is drawn you find the mean of the sample, and the sample standard deviation, s. With all of this in hand you use the formula above to construct a single value of t. If you repeated this operation many, many times, the ditribution of the different t values you get from each trial would form the curve called the t-distribution with n-1 degrees of freedom.

The image at right shows a comparison of the t-distribution with one degree of freedom (dark) and the standard normal distribution (dotted). You can experiment with the impact of the size of the sample, n, on the shape of the distribution with this java applet . For small values of n the curve is leptokurtic or flattened in comparison to the Standard Normal curve. It is lower at its peak than the Normal curve, but has higher density at the extreme regions of the tails.

The t-distribution with n=2 (or 1 Degree of freedom) was actually used at least as early as 1824 when Poisson wrote of it (not by that name). The distribution was also briefly explored by F Y Edgeworth (1883) where he calls it the subexponential distribution.

The t-distribution with only one degree of freedom is also called a Cauchy distribution. It can be written as . The curve was frequently studied in the early stages of statistics as an alternative to the normal curve for the distribution of errors. Although the distributions are named for Cauchy, they were earlier studied by Fermat, and numerous others including Huygens, Poisson, and Maria Agnesi.

In the form it was studied by Agnesi, it has often been called the "Witch of Agnesi.". A nice visual for how the "witch" is derived geometrically is found at Mathworld.com The origin of the name seems to have two explanations. One is that the Agnesi used the term "averisera" for the versed (turned) sine curve, and was subsequently mis-translated by John Colson who was Lucasian Professor of Mathematics at Cambridge. [See the text box below for the story according to Shirley Gray of California State Univ.] According to Stephen Stigler, however, Agnesi had used the term "la versiera" and stated that it meant witch or she-devil. Stigler also adds that she was not the first to use that term for the curve. Guido Grandi had used the same term in 1718, "explaining that the curve had arisen from a consideration of the 'semi versi' versed sine, and that he would call it 'versiera' after the latin word 'versoria'." In fact, says Stigler, "Although some have interpreted this to mean that versoria meant versed sine, the only relevant definition of versoria given in dictionaries of that time is 'a turning or twisting around'... Versiera is not the Italian word for Versoria but, rather, is the feminine form of 'avversario', sometimes used to mean devil..." Stigler goes on to suggest that Guido may have been indulging in a little humorous play on words and may have been suggesting that the curve resembled a woman's breast.

On This Day in Math - November 14

    



He who understands Archimedes and Apollonius will admire less 
the achievements of the foremost men of later times.
~Gottfried Leibniz

The 318th day of the year; According to Police chief Wiggum on The Simpsons; 318 is the Police code for waking a police officer in episode 5F06 Reality Bites.

If 22 is partitioned into distinct integer parts in all possible ways, there will be 318 total parts.

318 is a palindrome in base 9, 3839



EVENTS

1673 Christopher Wren is knighted. *@HookesLondon

1680 The Great Comet of 1680, Kirch's Comet, and Newton's Comet, has the distinction of being the first comet discovered by telescope. Discovered by Gottfried Kirch on 14 November 1680, New Style, it became one of the brightest comets of the 17th century--reputedly visible even in daytime--and was noted for its spectacularly long tail. Passing only 0.4 AUs from Earth on 30 November, it sped around an incredibly close perihelion of .006 AU (898,000 km) on 18 December 1680, reaching its peak brightness on 29 December as it rushed outward again. It was last observed on 19 March 1681. As of December 2010 the comet was about 252.1 A.U. from the Sun. While the Kirch Comet of 1680-1681 was discovered and subsequently named for Gottfried Kirch , credit must also be given to the Jesuit, Eusebio Kino, who charted the comet’s course. During his delayed departure for Mexico, Kino began his observations of the comet in Cadíz in late 1680. Upon his arrival in Mexico City, he published his Exposisión astronómica de el [sic] cometa (Mexico City, 1681) in which he presented his findings. Kino’s Exposisión astronómica is among one of the earliest scientific treatises published by a European in the New World. Aside from its brilliance, it is probably most noted for being used by Isaac Newton to test and verify Kepler's laws. *Wik  

The orbit of the comet of 1680, fit to a parabola, as shown in Isaac Newton's Principia



1750 Euler creates the term “edge” for polyhedral. In a letter to Christian Goldbach, Euler writes, “the junctures where two faces come together along their sides, which, for lack of an accepter term, I call edges.” *Dave Richeson, Euler’s Gem, pg 63  "It astonishes me that these general properties of stereometry have not, as far as I know, been noticed by anyone else". *Carlo Beenakker at Math Overflow



1757 After incremental computations of the gravitational influences and motion of Jupiter and Saturn on the predicted return of Halley's comet, Alexis-Claude Clairaut presents the results to the Academies de Sciences. The computational work of the team of Clairaut, with La Lande and Nicole-Reine Lepaute, (having removed Saturn from the last few months calculations to speed the results) had predicted a window of arrival between March 15 and May 15 (1758). The unruly comet reached perihelion on the 13th of March.
This was one of the first "division of Labor" efforts to use human calculators to work on a joint project,  Their error was almost exclusively the result of the effect of Uranus and Neptune, planets unknown at that time.
 *David A Grier, When Computers Were Human




In 1910, the first airplane flight from a ship was made by Eugene Ely from the bow of the scout cruiser Birmingham, anchored at the Hampton Roads Yatch Clubhouse at Willoughby Spit. His runway was 83 feet long, with a five degree slope, but because the plane itself was 57 feet long, the available runway for takeoff was only 26 feet. He then flew through fog and rain to Hampton Rpads, Va. For his effort, he won a $5,000 prize offereed by John Barry Ryan. Ely was a civilian pilot for the Curtiss Aviation Company. The following year, 18 Jan 1911, Ely made another first in history when he landed on the battleship USS Pennsylvania in San Francisco Bay.
Ely made the first attempt to fly from shore to a warship and alight thereon the 18th inst. [18 Jan 1911]. The photographs reproduced herewith show Ely's Curtiss biplane just as it was about to alight upon the special platform and also after it had alighted and and was being brought to rest by a score of ropes stretched across the platform above the two rails which ran its entire length. These ropes were attached to sand bags at each end, and they were found to act as an efficient brake in checking the momentum of the machine. Although Ely had floats fitted beneath the lower plane on each side of the center section, this proved to be an unnecessary precaution. He made the flight to the “Pennsylvania,” which was anchored amid the dense shipping in San Francisco Bay, in 13 minutes, and arrived upon the warship at three minutes before 11 A.M. In flying the 12 miles from Selfridge field, he had risen to a height of 2,000 feet and passed over the San Bruno mountains. Soon after the start Ely was espied by the sailors in the fighting tops of the warship, a tiny speck above the mountains. The speck grew larger as it rapidly approached and the surfaces of the biplane were outlined against the sky. As it neared the harbor Ely's air craft descended rapidly until, when he flew over the “West Virginia'' and the other smaller vessels, he was only 150 to 200 feet in the air. At just the right moment he shut off his motor and glided down to the platform on the stern of the “Pennsylvania.” He struck this 32 x 127-foot platform 25 feet from its outer end, which sloped downward 4 feet in 10.
After a rесерtion on shipboard lasting an hour, Ely started from the vessel without any difficulty and flew back to the aviation field again in 13 minutes.

Thus was accomplished the first round trip flight from shore to ship. Ely had previously flown from ship to shore in Hamilton Roads last November. In both instances he won a prize of $500 offered by the U. S. Aeronautical Reserve. His excellent flights have increased interest in the aeroplane for naval use and will no doubt help in getting through Congress the appropriation of $25,000 recently asked for by Secretary of the Navy Meyer for experiments in aviation. The success of Glenn Curtiss in rising from the surface of the water in his machine mounted on floats at San Diego on the 26th of January, will also help along the cause of aviation in the Navy.*TIS




1922 The British Broadcasting Company's first weather forecast was broadcast on radio on November 14, 1922 in London. The forecast was prepared by the Met Office. From March 26, 1923, these weather forecasts became a daily service.
It appears the forecast said that London was foggy that day.  (And the day before and the day after but.... progress is progress..... Okay, I've been called out by a Londener who said " True, ground-level fog (where visibility drops below 1,000 meters) is rare in modern London"  Now all I need to figure out is which parts of London are modern.  😏


1949 France issued stamps honoring Voltaire and the Comte de Buffon (1707-1778). [Scott #B239, B241]. *VFR






1985 The discovery of the first fullerenes is announced in the 14 Nov 1985, issue of the journal Nature. Robert F. Curl, Jr. American chemist who with Richard E. Smalley and Sir Harold W. Kroto discovered the first fullerene, a spherical cluster of carbon atoms, in 1985. The discovery opened a new branch of chemistry, and all three men were awarded the 1996 Nobel Prize for Chemistry for their work. In Sep 1985 Curl met with Kroto of the University of Sussex, Eng., and Smalley, a colleague at Rice, and, in 11 days of research, they discovered fullerenes. *TIS
In 1991 After the C60 Fullerenes discovery and Nobel Prize the session of the House of Lords entertained a question from Lord Errol of Hale as to "What steps the government was taking to encourage the use of Fullerenes in science and industry?" The question prompted questions on what was a Fullerene, what shaped did it have and finally, this brilliant exchange:
Lord Campbell of Alloway: "My Lords, what does it do?"
Lord Reay: "My Lords, it is thought that it may have several possible uses... All that is speculation. It may turn out ot have no uses at all."
Earl Russell: "My Lords, can one say that it does nothing in particular, and does it very well." *Siobhan Roberts, King of Infinite Space

The C_60 Fullerine  



Smalley


Robt Curl



Kroto




BIRTHS

1845 Ulisse Dini (14 November 1845 – 28 October 1918) was an Italian mathematician and politician born in Pisa. One of his professors was Enrico Betti. In 1865, a scholarship enabled him to visit Paris, where he studied under Charles Hermite as well as Joseph Bertrand, and published several papers. In 1866, he was appointed to the University of Pisa, where he taught algebra and geodesy. In 1871, he succeeded Betti as professor for analysis and geometry. From 1888 until 1890, Dini was rettore (chief executive) of the Pisa university, and of the Scuola Normale Superiore from 1908 until his death in 1918. He was also active as a politician: in 1871 he was voted into the Pisa city council, and in 1880, he became a member of the Italian parliament.
Dini worked in the field of analysis during a time when it was begun to be based on rigorous foundations. He proved a criterion for the convergence of Fourier series and investigated the potential theory and differential geometry of surfaces, based on work by Eugenio Beltrami.
The implicit function theorem is known in Italy as the Dini's theorem.*Wik



1882 Robert Lee Moore (14 November 1882 – 4 October 1974) was an American mathematician, known for his work in general topology and the Moore method of teaching university mathematics. Moore entered the University of Texas at the unusually low age of 16, in 1898, already knowing calculus thanks to self-study. He completed the B.Sc. in three years instead of the usual four; his teachers included G. B. Halsted and L. E. Dickson. After a year as a teaching fellow at Texas, he taught high school for a year in Marshall, Texas.
An assignment of Halsted's led Moore to prove that one of Hilbert's axioms for geometry was redundant. When E. H. Moore (no relation), who headed the Department of Mathematics at the University of Chicago, and whose research interests were on the foundations of geometry, heard of Robert's feat, he arranged for a scholarship that would allow Robert to study for a doctorate at Chicago. Oswald Veblen supervised Moore's 1905 thesis, titled Sets of Metrical Hypotheses for Geometry.
Moore then taught one year at the University of Tennessee, two years at Princeton University, and three years at Northwestern University. In 1910, he married Margaret MacLelland Key of Brenham, Texas; they had no children. In 1911, he took up a position at the University of Pennsylvania.
In 1920, Moore happily returned to the University of Texas at Austin​ as an associate professor, and was promoted to full professor three years later. In 1951, he went on half pay, but continued to teach his habitual five classes a year, including a section of freshman calculus, until the University authorities forced his definitive retirement in 1969, his 87th year. In 1973, the University of Texas honored him by giving the name Moore Hall to a new building housing the physics, mathematics, and astronomy departments.*Wik
 In 2016, students demanded the building be renamed because of Moore's racist treatment of African American students.  
*Wik



Paulette Libermann (November 14 1919 in Paris ,July 10 2007 in Montrouge ) was a French mathematician , her primary work was in differential geometry and symplectic geometry employed. 
Libermann's research involved many different aspects of differential geometry and global analysis. In particular, she worked on G-structures and Cartan's equivalence method, Lie groupoids and Lie pseudogroups, higher-order connections, and contact geometry.
In 1987 she wrote together with Charles-Michel Marle one of the first textbooks on symplectic geometry and analytical mechanics.*Wik





1943 Peter Norton (November 14, 1943 - )was born in Aberdeen, Washington. Norton would first come to note for producing tools that could retrieve erased data from DOS disks that would eventually be compiled into suite called Norton Utilities. Norton founded Peter Norton Computing, which produced both software utilities as well as publishing several manuals and books. In 1990, Norton sold his company to Symantec, which would keep the Norton name alive for more than a decade following the purchase. He currently heads up The Peter Norton Family Foundation, which is a major philanthropic group supporting the arts and human social services. *CHM





DEATHS

1716 Gottfried Wilhelm Leibniz  (1 Jul 1646, 14 Nov 1716) spent his closing years enfeebled by disease, harassed by controversy, embittered by neglect; but to the last he preserved the indomitable energy and power of work to which is largely due the position he holds as, more perhaps than any one in modern times, a man of almost universal attainments and almost universal genius. At Hanover, Eckhart, his secretary, was his only mourner; "he was buried", says an eyewitness, "more like a robber than what he really was, the ornament of his country."*Georgi Dalakov, History of Computers web-site ---
 German philosopher, mathematician, and political adviser, important both as a metaphysician and as a logician and distinguished also for his independent invention of the differential and integral calculus. Through meeting with such scholars as Christian Huygens in Paris and with members of the Royal Society, including Robert Boyle, during two trips to London in 1673 and 1676, Leibniz was introduced to the outstanding problems challenging the mathematicians and physicists of Europe. Leibniz's independently discovered differential and integral calculus (published 1684), but became involved in a bitter priority dispute with Isaac Newton, whose ideas on the calculus were developed earlier (1665), but published later (1687). *TIS




1798 Naonobu Ajima  (1732 – May 20, 1798) was a Japanese mathematician and astronomer who developed a theory of integration. Ajima's work leaned towards geometry despite the strong algebraic numerical tradition in the Seki school. He developed methods of integration, developing the 'yenri' method which had been devised earlier and was used to find the area of a circle using inscribed polygons in a similar manner to the methods of Archimedes. Ajima refined the method subdividing the chord of an arc into equal small segments, so producing a method similar to that of the definite integral. He presented this in Kohai jutsu kai, giving a method which is the high point that traditional Japanese mathematics reached in methods of integration Immediately after developing this method of integration, Ajima developed a method for computing volumes by double integration. The method was developed to solve the problem of finding the volume of the intersection of two cylinders and he presented it in Enchu kokuen jutsu.
Ajima also solved the Malfatti problem. It is today called the Malfatti Problem since it was posed in 1803 by Gian Francesco Malfatti, but Ajima's contributions were made around 30 years earlier. The problem is, given an arbitrary triangle, find how to place three non-overlapping circles so that the area of that part of the triangle not covered by a circle is a minimum. Malfatti assumed that the solution would involve three circles, each of which is tangent to the other two. It is precisely the problem of maximizing the area of the three mutually tangent circles that Ajima solved in Fukyu sampo. However, Malfatti's assumption is wrong and it was shown in 1992 that to maximize the area of the three non-overlapping circles, they are never mutually tangent. This, of course, is not relevant to Ajima's problem which is only posed in terms of maximizing the area of three non-overlapping mutually tangent circles.
After Ajima's death, he was buried in the Jorin-jo Temple, Mita, Tokyo, and his grave can still be visited today. *SAU



1886 Alexandre-Emile Beguyer de Chancourtois (20 Jan 1820; 14 Nov 1886) French geologist who was the first to arrange the chemical elements in order of atomic weights (1862). De Chancourtois plotted the atomic weights on the surface of a cylinder with a circumference of 16 units, the approximate atomic weight of oxygen. The resulting helical curve which he called the telluric helix brought closely related elements onto corresponding points above or below one another on the cylinder. Thus, he suggested that "the properties of the elements are the properties of numbers." Although his publication was significant, it was ignored by chemists as it was written in the language of geology, and the editors omitted a crucial explanatory table. It was Dmitry Mendeleyev's table published in 1869 that became most recognized.*TIS



1919 John Aitken (18 Sep 1839, 14 Nov 1919) Scottish physicist and meteorologist known for his research work on atmospheric dust, the formation of dew, cyclones and evaporation. He invented the koniscope to detect and study atmospheric dust particles. He determined that condensation of atmospheric water vapor from clouds and fogs begins on the surface of microscopic particles (now known as Aitken nuclei) as a crucial step in the formation of rain and dew. Combustion produces a profusion of such particles. Suffering from ill health, he worked from a laboratory in his Falkirk home. Much of his work was published in the journals of the Royal Society of Edinburgh. *TIS



1934 Alice Liddlell Hargraves ( 4 May 1852 – 16 November 1934) died, age 82. She was the Alice of Lewis Carroll's classic, Alice’s Adventures Underground. *VFR
For most of her life, she lived in and around Lyndhurst in the New Forest. After her death she was cremated and her ashes were buried in the graveyard of the church of St. Michael & All Angels, Lyndhurst *Wik


Alice had a noteworthy connection later in life with Prince Leopold, Duke of Albany (1853–1884), the youngest son of Queen Victoria. Their relationship is one of those gentle, slightly romantic footnotes in Victorian history.
They met in the early 1870s at Oxford, where Leopold studied at Christ Church—the same college where Alice’s father was Dean and where Lewis Carroll was a lecturer in mathematics.

Leopold and Alice formed a warm and close friendship, and many historians believe he fell in love with her.   Besides socializing at Oxford, Leopold visited the Liddell family at their home, and the relationship was well-known among friends.
Many people have offered reasons that they did not marry:

Queen Victoria had strong opinions about her children’s marriages and  Alice, though from a distinguished family, was still a commoner and not considered a suitable royal match for a prince of the blood.  Evidence suggests that the romance was quietly discouraged by the Queen, and the relationship drifted apart.
Even though they married other people, both Alice and Leopold seem to have carried a fondness for each other:  In 1880, Alice married Reginald Hargreaves and gave one of her sons the middle name Leopold.  In the same year, Prince Leopold married Princess Helen of Waldeck-Pyrmont—and named his daughter Alice.  These mirrored namings are often cited as touching signs that the two continued to honor each other’s memory.

Prince Leopold



1954 Ernst Fischer (12 July 1875; Vienna, Austria – 14 November 1954) He worked alongside both Mertens and Minkowski at the Universities of Vienna and Zurich, respectively. He later became professor at the University of Erlangen, where he worked with Emmy Noether.
His main area of research was mathematical analysis, specifically orthonormal sequences of functions which laid groundwork for the emergence of the concept of a Hilbert space.
The Riesz–Fischer theorem in Lebesgue integration is named in his honour. *Wik



1971 Hanna Neumann (2 Feb 1914 in Lankwitz, Berlin, Germany - 14 Nov 1971 in Ottawa, Canada) worked in group theory. Her thesis examined free products with amalgamation. Later she worked on varieties of groups and her book Varieties of Groups (1967) is a classic.*SAU



2006 
Gustave Choquet ( French: [ɡystav ʃɔkɛ] ; 1 March 1915 – 14 November 2006) was a French mathematician .
Choquet was born in Solesmes, Nord . His contributions include work in functional analysis , potential theory , topology and measurement theory . He is known for creating the Choquet theory , the Choquet integral and the theory of capacities .
He did postgraduate work at the École Normale Supérieure Paris where his advisor was Arnaud Denjoy . He was Professor at the University of Paris (subsequently Paris VI ) from 1940 to 1984 and was also Professor at the École Polytechnique from 1960 to 1969. His honors and awards included being a Member of the Académie des Sciences , and an Officier of the Légion d'Honneur .
His students include Haïm Brezis , Gilles Godefroy , Nassif Ghoussoub , Michel L. Lapidus , and Michel Talagrand .
He was married to mathematician and mathematical physicist Yvonne Choquet-Bruhat , with whom he had a son Daniel and a daughter Geneviève . He died in Lyon in 2006.

His wife, Yvonne Choquet-Bruhat ( 29 December 1923 – 11 February 2025) was the first woman to be elected to the French Academy of Sciences and was a Grand Officer of the Legion of Honour. [Marguerite Perey was elected in 1962 as a corresponding member.
She was therefore the first woman elected to the Academy in any capacity.

Yvonne Choquet-Bruhat was the first woman elected as a full (titulary) member: elected 1979; the first female full member in the Academy’s 300-year history. 
Marie Curie was never admitted to the French Academy of Sciences.  She ran for election in 1911 and came very close to winning, but she lost by just two votes to physicist Édouard Branly. The vote was widely understood to have been influenced by gender bias , nationalism  (Curie’s Polish origins were held against her), antisemitic press attacks (even though she was not Jewish), which surged around the same time due to her relationship with Paul Langevin (He was still married). After this election, the Academy effectively closed the door to her, and she never stood again. The Academy did not admit any woman at all until 1962, long after Curie’s death.






2014 Eugene Borisovich Dynkin ( May 11, 1924 — 14 November 2014) was a Soviet and American mathematician. He has made contributions to the fields of probability and algebra, especially semisimple Lie groups, Lie algebras, and Markov processes. The Dynkin diagram, the Dynkin system, and Dynkin's lemma are named for him.
In 1968, Dynkin was forced to transfer from the Moscow University to the Central Economic Mathematical Institute of the USSR Academy of Sciences. He worked there on the theory of economic growth and economic equilibrium. He remained at the Institute until 1976, when he emigrated to the United States. In 1977, he became a professor at Cornell University, where he died in 2014. *Wik



2022 Kristie Irene Macrakis (March 11, 1958 – November 14, 2022) was an American historian of science, author and professor in the School of History, Technology and Society at the Georgia Institute of Technology. She was the author or editor of five books and was widely known for her work at the intersection of history of espionage and history of science and technology.

Macrakis received her PhD in the history of science at Harvard University. After teaching at Harvard University for a year as a lecturer, Macrakis spent a year in Berlin on an Alexander von Humboldt Foundation Chancellor's Scholar for Future Leaders, before taking up a position at Michigan State University where she advanced from Assistant to Full Professor, before taking up a Full Professor position at Georgia Tech.

Prisoners, Lovers, and Spies (2014) and Seduced by Secrets (2008) were her single authored books. Nigel Jones wrote in The Spectator that Prisoners, Lovers and Spies is "beguilingly informative and sweeping survey of hidden communication.]Kirkus Reviews named it one of the best nonfiction books of 2014 and called it "lively...engaging" and "An engrossing study of unseen writing and the picaresque misadventures of those who employ it."

Seduced by Secrets was hailed as the "best book" on the Ministry for State Security by Benjamin Fischer in the International Journal of Intelligence and CounterIntelligence,[while Joseph Goulden, of the Washington Times, gave it "a five cloak-and-dagger rating. Good reading for the specialist and the layman alike."

Macrakis was also the author of numerous articles, both scholarly and popular. While a graduate student at Harvard she found that the Rockefeller Foundation funded science in Nazi Germany; that work was covered in the Frankfurter Allgemeine Zeitung. (Frankfurter Allgemeine Zeitung, 29 October 1986). Her most widely read popular magazine article is "The Case of Agent Gorbachev," published in American Scientist.

Following a brief illness, Macrakis died on November 14, 2022, at the age of 64.





Credits :
*CHM=Computer History Museum
*FFF=Kane, Famous First Facts
*NSEC= NASA Solar Eclipse Calendar
*RMAT= The Renaissance Mathematicus, Thony Christie
*SAU=St Andrews Univ. Math History
*TIA = Today in Astronomy
*TIS= Today in Science History
*VFR = V Frederick Rickey, USMA
*Wik = Wikipedia
*WM = Women of Mathematics, Grinstein & Campbell





Friday, 13 November 2026

Once More, Why we use m for Slope

   Another from the "most popular" hits on my way-back machine from 2013. Hope you enjoy........



Over the many years I taught I developed a keen interest in the origin and use of the symbols and terminology of math. When the internet came around I jumped in pretty early with a web page on Mathwords, contributing on the Dr Math and Teacher to Teacher support Math Forum, and for several years, this blog. Over that time there are few questions that come up more often than the reason for the letter m as the symbol for slope in the standard American (and it does seem to be mostly American) linear slope intercept equation form, y = mx + b.
Almost no one seems to ask about the b, which is even more curious to me.

Interestingly, m for slope has led to more mis-history speculation in classrooms than any other topic, with the possible exception of the life of that Great American-Indian Mathematician, Chief Soh Cah Toa.
Here is what I have found about the m for slope history.


Many variations of where the idea of M for slope originated seem to be mostly myth. One of the most common is that the letter was used by Descarte because it was the first letter of some French word or another that related. In a post to the AP Stats discussion list some years ago, Hector Hirigoyen shared the following story:
I was told by Mary Dolciani herself, that the SMSG group "decided "to use y=mx+b because of the French (Descartes, I presume)-"montant"; I found it strange because the "logical word" would be "pente"(which is slope (and the standard term in Spanish is pendiente, which matches this). However, several years ago, while visiting a French high school, I noticed the teacher used y=sx+b. I inquired, and she said because of the "American" word "slope." I believe they are using ax+b for the most part these days.

A similar story was shared by Paul Foerster:
I can confirm Hector Hirigoyen's statement about the origin of "m" for slope. Hector was in the audience when I did a presentation at a math teachers' meeting in Florida about 1986 or 1987. His point was that "m" came from the French "montant," meaning "the rise." Because he taught AP French as well as mathematics, it seemed like a logical conclusion.
I was so thrilled with this new knowledge that I told it to my BC Calculus class when i returned to San Antonio. To add to the credibility, I asked Cassandra Stapfer, my exchange student from Paris, to confirm that this was correct. Cassandra said, "montant does mean 'the rise,' but in France we use 's' for 'slope'."So much for my brilliant discovery!

Here are several other clips from postings about the topic on a discussion group about math history.
In his "Earliest Uses of Symbols from Geometry" web page, ... Jeff Miller gathered the following information: Slope. The earliest known use of m for slope is an 1844 British text by Matthew O'Brien entitled _A Treatise on Plane Co-Ordinate Geometry_ [V. Frederick Rickey]. George Salmon (1819-1904), an Irish mathematician, used y = mx + b in his _A Treatise on Conic Sections_, which was published in several editions beginning in 1848. Salmon referred in several places to O'Brien's Conic Sections and it may be that he adopted O'Brien's notation.


According to Erland Gadde, in Swedish textbooks the equation is usually written as y = kx + m. He writes that the technical Swedish word for "slope" is "riktningskoefficient", which literally means "direction coefficient," and he supposes k comes from "koefficient."
According to Dick Klingens, in the Netherlands the equation is usually written as y = ax + b or px + q or mx + n. He writes that the Dutch word for "slope" is "richtingscoefficient", which also means "direction coefficient." In Austria k is used for the slope, and d for the y-intercept. In Uruguay the equation is usually written as y = ax + b or y = mx + n, and the "slope" is called "pendiente", coeficiente angular", or "parametro de direccion".

It is not known why the letter m was chosen for slope; the choice may have been arbitrary. John Conway has suggested m could stand for "modulus of slope." One high school algebra textbook says the reason for m is unknown, but remarks that it is interesting that the French word for "to climb" is monter. However, there is no evidence to make any such connection. Descartes, who was French, did not use m. In _Mathematical Circles Revisited_ (1971) mathematics historian Howard W. Eves suggests "it just happened."

Jeff Miller's web site cited above now has updated the earliest use of m for slope.
The earliest known use of m for slope appears in Vincenzo Riccati?s memoir De methodo Hermanni ad locos geometricos resolvendos, which is chapter XII of the first part of his book Vincentii Riccati Opusculorum ad res Physica, Mathematicas pertinentium (1757):
Propositio prima. Aequationes primi gradus construere. Ut Hermanni methodo utamor, danda est aequationi hujusmodi forma y = mx + n, quod semper fieri posse certum est. (p. 151)
The reference is to the Swiss mathematician Jacob Hermann (1678-1733). This use of m was found by Dr. Sandro Caparrini of the Department of Mathematics at the University of Torino.

I just checked Jeff's site again and found the following list of notes from his readers:
In 1830, Traite Elementaire D'Arithmetique, Al'Usage De L'Ecole Centrale des Quatre-Nations: Par S.F. LaCroix, Dix-Huitieme Edition has y = ax + b [Karen Dee Michalowicz].
Another use of m occurs in 1842 in An Elementary Treatise on the Differential Calculus by Rev. Matthew O'Brien, from the bottom of page 1: "Thus in the general equation to a right line, namely y = mx + c, if we suppose the line..." [Dave Cohen].
O'Brien used m for slope again in 1844 in A Treatise on Plane Co-Ordinate Geometry [V. Frederick Rickey].
George Salmon (1819-1904), an Irish mathematician, used y = mx + b in his A Treatise on Conic Sections, which was published in several editions beginning in 1848. Salmon referred in several places to O'Brien's Conic Sections and it may be that he adopted O'Brien's notation. Salmon used a to denote the x-intercept, and gave the equation (x/a) + (y/b) = 1 [David Wilkins].
Karen Dee Michalowicz has found an 1848 British analytic geometry text which has y = mx + h.
The 1855 edition of Isaac Todhunter's Treatise on Plane Co-Ordinate Geometry has y = mx + c [Dave Cohen].
In 1891, Differential and Integral Calculus by George A. Osborne has y - y' = m(x - x').
In Webster's New International Dictionary (1909), the "slope form" is y = sx + b.
In 1921, in An Introduction to Mathematical Analysis by Frank Loxley Griffin, the equation is written y = lx + k.
In Analytic Geometry (1924) by Arthur M. Harding and George W. Mullins, the "slope-intercept form" is y = mx + b.
In A Brief Course in Advanced Algebra by Buchanan and others (1937), the "slope form" is y = mx + k.
According to Erland Gadde, in Swedish textbooks the equation is usually written as y = kx + m. He writes that the technical Swedish word for "slope" is "riktningskoefficient", which literally means "direction coefficient," and he supposes k comes from "koefficient."
According to Dick Klingens, in the Netherlands the equation is usually written as y = ax + b or px + q or mx + n. He writes that the Dutch word for slope is "richtingscoëfficiënt", which literally means "direction coefficient."
In Austria k is used for the slope, and d for the y-intercept.
According to Julio González Cabillón, in Uruguay the equation is usually written as y = ax + b or y = mx + n, and slope is called "pendiente," "coeficiente angular," or "parametro de
direccion."
According to George Zeliger, "in Russian textbooks the equation was frequently written as y = kx + b, especially when plotting was involved. Since in Russian the slope is called 'the angle coefficient' and the word coefficient is spelled with k in the Cyrillic alphabet, usually nobody questioned the use of k. The use of b is less clear."

So why do we use m? Mostly habit... after all, you gotta' use something. I would hope some of my international readers would tell us what THEY use for the linear coefficient symbol in this slope intercept form of the equation; especially if they actually do use m.
Stay tuned.

ADDENDUM:

I got a couple of comments telling me that m is used for slope in Germany (y=mx+t) by Thony Christie, and one from Luke Robinson that in the UK they use  y = mx+c.
Maria Miller added that, "In Finland, it is y = kx + b, and the term for 'k' is 'kulmakerroin' - literally 'angle multiplier'. "
And recently, Dave Marain, whose wonderful blog is appropriately titled Math Notations, sent the following:

" Pat, the best comment on my blog from years ago was from an Australian educator who said down under they spell it mlope"

I also found a couple of older books  that show this was used in the UK at least into the mid 19th century.  Charles Joseph Hughes in his Useful formulæ, chiefly in the pure mathematics (1859) uses  y=mx+c in a book that says it is for the use of candidates preparing for Addiscomb, Sandhurst, Woolwich and the Universities  (with the note that it is "to be committed to memory").

An even older use in 1812 was in an American edition of Hutton's Course of Mathematics for the use of Academies.  Hutton (Adrian) uses x=ny+c and y=mx+d in the same line, so his use seems more along the line of letting middle letters (k,l,m,n) stand for pronumerals (a word I derived from pronouns to indicate numbers that represented some single unspecified value) and x,y,z to represent true variable quantities.    This is from Hutton's 5th and 6th edition and was "revised and corrected" by Robert Adrian.  Adrian was an Irish-American considered one of the brightest mathematicians in the early 19th century.  He independently found a method of least squares independent of Gauss (in fact published before Gauss' work was published).
It seems the use of middle letters in the alphabet for the linear coefficient of terms was pretty common near the beginning of the 19th century.  For example, in factoring a trinomial the 1804The mathematical correspondent: containing, new elucidations, discoveries, and improvements, in various branches of the mathematics says "will always be the product of two rational factors (mx+p)(nx+q)."

And about four years after the first writing, a tweet fro Mathematical_A shared that, "Earliest known use of m for gradient in print is Vincenzo Riccati, 1757.  He  used y=mx+n.



Prompted by a comment to this re-posting, I was reminded of a nice anecdote about the "Why m?" discussion from the original post, so I include it now:  "It just happened!"