Thursday, 20 August 2026

On This Day in Math - August 20

   



Mathematics is a form of poetry which transcends poetry in that it proclaims a truth; a form of reasoning which transcends reasoning in that it wants to bring about the truth it proclaims; a form of action, of ritual behavior, which does not find fulfillment in the act but must proclaim and elaborate a poetic form of truth.
~Salomon Bochner


The 232nd Day of the Year
232 is the maximum number of regions that the plane can be divided into with 21 lines (how many of the regions would be of infinite area?)

232 is a palindrome in base ten, but no other base from 2-9

There are 232 bracelets possible with 8 beads of one color and seven of another.

 And from Derek Orr
232 is sum of the cubes of the factorials of its digits,
232 = (2!)3 + (3!)3 + (2!)3

and 232 the sum of the first 11 Fibonacci numbers. 232 = 1+1+2+3+5+8+13+21+34+55+89

If you add up all the proper divisors of a number, n, they can be less than n, as 231 is(deficient), equal to n (perfect, like 6 or 28) or abundant. 12 is the smallest abundant number. Nicomachus wrote only of even numbers because he thought all odd numbers were deficient, but he was wrong. The 232nd abundant number is odd, 945.

If you raise 232 to the power of the product of its digits, and then add the sum of its digits, you get a prime. The only other known number with this property is 187. *Prime Curios  
232^12 + 7 = 24313966763341113270967730183

232 /4 = 58, so 59^2 - 57^2 = 232. 232 / 8 = 29 so 31^2-27^2 = 232.

Because 58 is a sum of two squares, 232 is also. 58 =7^2 + 3^2, 232 = 14^2 + 6^2. Students might use this to find the sum of two squares for 522 = 9 x 58.

232 is another balanced binary, with four of each ones and zeros, 

232 is one less than a Fibonacci Prime.




EVENTS

1601 Pierre Fermat, the child of Claire de Long is baptized in the town of Beaumont de Lomange near Toulouse. almost thirty years later he would marry his mother's distant cousin. *André Weil, Number Theory: An Approach Through History from Hammurabi to Legendre
There is a statue and museum to him in the town.




1638 William Oughtred writes to instrument maker Elias Allen with instructions for the first physical pair of slide rules using his method. Oughtred had invented the rules as early as 1620, and definitely written about them by 1633, but as he says in the opening of his letter, he had never made one before: “I have here sent you directions (as you requested me being at Twickenham) about the making of the two rulers”. He would continue, “would gladly see one of [the two parts of the instrument] when it is finished: wch yet I never have done”. The slide rule that Allen created seems no longer to exist, but a reverse image printed from the rule, perhaps to show to Oughtred still remains.
*Boris Jardine, Cambridge University Library Special Collections

Oughtred's method used two rules with logarithmic scales that were positioned so that one slid against the other. Within two decades, the first slide rule with the scales bound together was created by Robert Bissaker. This is the oldest slide rule still existing today and is in the Science Museum, London.


Oughtred is also known for introducing the X for multiplication, and the double colon, ::, for ratio. His use of a vertical bar to separate decimals from whole numbers was not well accepted.


 


1699 Newton's name introduced outside the Cambridge area. In 1669 Barrow had brought Newton a copy of Nicholas Mercator's Logarithmotechnia, which included the infinite series for ln(1+x). Newton recognized this as a simple example of his more general work on infinite series during his annus mirabilis in Woolsthorpe. Newton began to share some of his work with Barrow, who talked him into allowing him to send some of it, anonymously, to John Collins, which he did. When Collins highly favorable responses were received, Newton allowed Barrow to identify him to Collins. Barrow's letter to Collins on this date was the first time Newton became known to the mathematical community outside Cambridge. *James Gleick, Isaac Newton




1809 Gauss writes to G. F. Parrot dean of the Philosophical faculty of Tartu University to explain why he could not accept the position of Professor of Mathematics and Astronomy. He chose instead to remain in Gottingen. *PB Notes

1858 The Darwin-Wallace paper was read before the Linnean Society July 1st, 1858 and published in their Proceedings Vol 3 1858. pp 45-62. on this day.
"On the Tendency of Species to form Varieties; and on the Perpetuation of Varieties and Species by Natural Means of Selection" ; By Charles Darwin, Esq., F.R.S., F.L.S.., & F.G.S., and Alfred Wallace​, Esq. Communicated by Sir Charles Lyell, F.R.S., F.L.S., and J.D. Hooker, Esq., M.D., V.P.R.S., F.L.S., &c. *Linnean Society

1910 Florence Nightingale was buried on 20 August in the family plot at East Wellow, Hampshire. An offer of burial in Westminster Abbey was refused by her relatives.  She died one week earlier. *Victorian Web Org  
Instead, she was laid to rest near her parents in St. Margaret's Churchyard, East Wellow. 

Three thousand tickets had been issued by the War Office for the memorial service at St. Paul’s Cathedral. Seven hundred nurses from all parts of the country attended, and the old veterans from the Chelsea Hospital, many of whom had fought in the Crimea. The King and Queen and the Queen-Mother and other members of the Royal Family were represented, and also the War Office and Army Council, the Corporation of London, the Prime Minister, Lord Morley, Earl Crewe and Mr. Haldane of the London Times newspaper.
The body was borne to the grave by six of her "children" of the British Army-sergeants drawn from the several regiments of the Guards. Her desire that only two persons should follow the coffin could not be fulfilled. The funeral arrangements were kept as private as was possible; but there was a wreath of flowers from people of every kind, age and degree, and the lane and churchyard were filled with a great crowd of men, women, and children, most of them poorly dressed. *Country Joe




1955 Observances were held on the Island of Samos commemorating the 2500th anniversary of the founding of the first school of philosophy by Pythagoras. Four postage stamps were issued by Greece. Naturally one of them illustrated the celebrated 47th proposition of Euclid, the Pythagorean Theorem, by a 3–4–5 triangle with squares erected on its sides.

1960 Two mongrel dogs, Belka(Little Squirrel) and Strelka(Little Arrow) became the first living creatures to perform a space flight and return safely to Earth. Korabl-Sputnik-2 (Spaceship Satellite-2), also known as Sputnik 5, was launched on August 19, 1960. Also on board were 40 mice, 2 rats and a variety of plants.
After a day in orbit, the spacecraft's retrorocket was fired and the landing capsule and the dogs were safely recovered. They were the first living animals to survive orbital flight. *Space Today Online





BIRTHS
 
1710 Thomas Simpson born (20 August 1710 – 14 May 1761). Best known to elementary calculus students for Simpson's rule, a method to approximate definite integrals. (this rule had been found 100 years earlier by Johannes Kepler, and in German is the so-called Keplersche Fassregel, "Kepler's barrel rule") The method actually uses a method of fitting parabolas to the function (a word not in use when Simpson lived) but is exact for polynomials up to a cubic. Apparently, the method that became known as Simpson's rule was well known and used earlier by Bonaventura Cavalieri (a student of Galileo) in 1639, later rediscovered by James Gregory (who Simpson succeeded as Regius Professor of Mathematics at the University of St Andrews) and was only attributed to Simpson because of the popularity of his math books in which it was included. *Wik




1779  Jöns Jakob Berzelius, (20 August 1779 – 7 August 1848) a Swedish chemist, was born Aug. 20, 1779.  Berzelius was part of the second generation of chemists who accepted the reform in chemical nomenclature proposed by Antoine Lavoisier and his confrères and set out to improve the nomenclature and flesh it out with newly discovered elements.  Berzelius did his share in the discovery department, being the first to isolate silicon (which he called silicium), selenium, and thorium, but he is best known for suggesting a new system of chemical symbols for the elements. John Dalton, the father of chemical atomism, had suggested using geometric symbols to represent each element: oxygen was a white circle, carbon a black circle, hydrogen a white circle with a dot in the center, etc.  A graphic display of Dalton's chemical symbols can be seen as the first image on our Scientist of the Day entry for Dalton. Berzelius proposed instead a symbolism based on the first, or the first and second, letters of the Latin names of the elements; in his system, oxygen was O, hydrogen was H, and carbon was C, while calcium was Ca, copper was Cu, and cobalt was Co. In the table above (second image), we see 31 of the 46 known elements and their symbols, along with their specific weights.

Berzelius proposed to represent compounds by combining these symbols; so water was 2H + O, while iron oxide (the red kind) was Fe + 3 0, as we see on another page, showing the remaining 15 chemical symbols and some proposed ways of representing compounds.  We have made some changes since Berzelius, but basically it is his system that we still use. When you look at a chart of the periodic table, the language you are reading is the nomenclature Berzelius initiated back in 1814.



*Linda Hall Org




1862 Paul Gustav Samuel Stäckel (20 August 1862, Berlin — 12 December 1919, Heidelberg) was a German mathematician, active in the areas of differential geometry, number theory, and non-Euclidean geometry. In the area of prime number theory, he used the term twin prime (Primzahlzwillinge i.e. "prime number twins") for the first time. *Wik

A strong proponent of mathematics education reform, he aligned with Felix Klein’s movement to modernize teaching methods by emphasizing functional thinking and applied mathematics over rigid classical curricula .
Stäckel served in WWI and later died in 1919 of a brain tumor in Heidelberg 





1863 Corrado Segre (20 August 1863, 18 May 1924) was an Italian mathematician who is remembered today as a major contributor to the early development of algebraic geometry.
Segre spent his entire career at the University of Turin, first as a student of Enrico D'Ovidio. In 1883 he published a dissertation on quadrics in projective space and was named as assistant to professors in algebra and analytic geometry. In 1885 he also assisted in descriptive geometry. He began to instruct in projective geometry, as stand-in for Giuseppe Bruno, from 1885 to 88. Then for 36 years he had the chair in higher geometry following D'Ovidio. Segre and Giuseppe Peano made Turin known in geometry.*Wik




1898 Leopold Infeld born (20 August 1898, Kraków – 15 January 1968, Warsaw), He was a Polish theoretical physicist. In 1948 he published Whom the Gods Love, a biographical novel about Evariste Galois. *VFR
He was awarded a doctorate at the Jagiellonian University (1921), worked as an assistant and a docent at the University of Lwów (1930–1933) and then as a professor at the University of Toronto between 1939 and 1950. In 1939 he married Helen Schlauch, an American mathematician and a graduate of Cornell.
He worked together with Albert Einstein at Princeton University (1936–1938). The two scientists co-formulated the equation describing star movements as well as co-wrote a popular science book The Evolution of Physics.
Infeld was one of the 11 signatories to the Russell–Einstein Manifesto in 1955, and is the only signatory never to receive a Nobel Prize. *Wik



1899 Salomon Bochner (20 Aug 1899; 2 May 1982) Galician-born American mathematician and educator responsible for the development of the Bochner theorem of positive-definite functions and the Bochner integral.*TIS
In 1925 he started work in the area of almost periodic functions, simplifying the approach of Harald Bohr by use of compactness and approximate identity arguments. In 1933 he defined the Bochner integral, as it is now called, for vector-valued functions. 





1905 Anna Adelaide Stafford Henriques (August 20, 1905 – November 28, 2004) was an American mathematician known for her pioneering role as a female researcher at the Institute for Advanced Study.

Anna was born on August 20, 1905, in Chicago, the first of five children in her family. Her father was a factory manager, and both her parents were children of immigrants. The family moved from Chicago to Wisconsin and Minnesota; her parents died in 1919 and the children moved again to a relative's home in Missouri.

Stafford graduated from high school in 1922 and, with a scholarship from the American Association of University Women, did her undergraduate studies at the Western College for Women, graduating in 1926 with a double major in Greek and mathematics and a minor in French. She became a school mathematics and science teacher in New York, Pennsylvania, and New Jersey, while attending summer classes at the University of Chicago.

Stafford completed a master's degree at Chicago in 1931, with a thesis on An Application of the Dihedral Group. She became interested in topology after seeing a talk by Raymond Louis Wilder, and became a student of Mayme Logsdon at Chicago, completing her doctorate in 1933 with a dissertation on Knotted Varieties.

In preparation for her postdoctoral studies, Stafford had applied to Princeton University to work with James Waddell Alexander II and Oswald Veblen, but was rejected because she was female. She then wrote directly to Veblen, who had been newly appointed to the Institute for Advanced Study (also in Princeton, New Jersey, but separate from the university), and after talking to him when he visited Chicago, she was accepted there.

Stafford became one of two women, with Mabel Schmeiser, in the first group of postdoctoral researchers to visit the Institute. She worked at the Institute from 1933 to 1935, and in order to support herself she also held a teaching position at a school in Princeton. She worked mornings at the school, freeing her afternoons to attend seminars at the Institute.

After her time at the Institute, Stafford decided to aim for a career teaching mathematics rather than one as a researcher. She became an instructor at the University of Nebraska, and then in 1937 moved to the University of Utah. At Utah, her students included Tom M. Apostol, who remembered her as his "best mathematics teacher". She also served there as president of the Utah branch of the National Council of Teachers of Mathematics.

In 1942, in Salt Lake City, she married (as his second wife) Douglas Emmanuel Henriques, an administrative judge. Although Stafford and her husband had no children together, they raised Henriques' teenage son and fostered two Navajo girls.

In 1956, a change of position for Stafford's husband caused their family to move to New Mexico. She gave up what was then an associate professorship in Utah and became a lecturer at St. Michael's College in Santa Fe, New Mexico, and soon after also at the University of New Mexico. She became a full professor at St. Michael's in 1962, and gave up her second position at the University of New Mexico. She eventually became department chair at St. Michael's (later the Santa Fe University of Art and Design), and retired as chair emeritus in 1971.

Stafford and her husband lived in their retirement in Falls Church, Virginia. Her husband died in 1987, and she died on November 28, 2004, in Bailey's Crossroads, Virginia.




1923 Tom Mike Apostol ( August 20, 1923 – May 8, 2016) was an American analytic number theorist and professor at the California Institute of Technology, best known as the author of widely used mathematical textbooks.

Apostol was born in Helper, Utah. His parents, Emmanouil Apostolopoulos and Efrosini Papathanasopoulos, were Greek immigrants. Apostolopoulos's name was shortened to Mike Apostol when he obtained his United States citizenship, and Tom Apostol inherited this Americanized surname.

Apostol received his Bachelor of Science in chemical engineering in 1944 at the University of Utah. He was particularly enthused by one of his mathematics teachers Anna Stafford Henriques. He said in the interview :-
My best mathematics teacher was Anna Henriques, who taught me college algebra and analytic geometry. She's in her nineties now and lives in a retirement complex in Virginia. I telephoned her recently, and she remembers me very well. 
By one of life's strange coincidences Tom and Anna share this date as a birthdate. A brief bio of her is also on this page.
 Master's degree in mathematics from the University of Washington in 1946, and a PhD in mathematics from the University of California, Berkeley in 1948. Thereafter Apostol was a faculty member at UC Berkeley, MIT, and Caltech. He was the author of several influential graduate and undergraduate level textbooks.

Apostol was the creator and project director for Project MATHEMATICS! producing videos which explore basic topics in high school mathematics. He helped popularize the visual calculus devised by Mamikon Mnatsakanian with whom he also wrote a number of papers, many of which appeared in the American Mathematical Monthly. Apostol also provided academic content for an acclaimed video lecture series on introductory physics, The Mechanical Universe.

In 2001, Apostol was elected in the Academy of Athens. He received a Lester R. Ford Award in 2005, in 2008, and in 2010. In 2012 he became a fellow of the American Mathematical Society.

Simply a beautiful book for math lovers





1925 
Elza Furtado Gomide (August 20, 1925 – October 26, 2013) was a Brazilian mathematician and the first woman to receive a doctorate in mathematics from the University of São Paulo, in 1950, and the second in Brazil. Gomide was involved in the creation of the Society of Mathematics of São Paulo and was elected head of the department of mathematics of the University of São Paulo in 1968. (The first Brazilian woman to receive a doctorate in mathematics and the first Brazilian woman to join the Brazilian Academy of Sciences was *Wik



1928  Professor Charles Bernard Bell, Jr., (Aug 20, 1928 - Oct 26, 2010)  one of the leading African American mathematicians of the twentieth century, was born in New Orleans, Louisiana on August 20, 1928. At age 19 he graduated from HBCU Xavier University in 1947 and earned his PhD. in mathematics from Notre Dame University, four years later, in 1953. From 1951 to 1955 he worked as a research engineer at Douglas Aircraft Company. After serving as an assistant professor at Xavier University for two years, he then spent a year at Stanford University as a research associate.

In 1958, Bell became the second African American professor hired at San Diego State University (SDSU) and became one of only a handful of Black professors at a predominantly white campus in that era. He served as advisor to the nearly all white student organization, the Interfaith Council. On leave from SDSU between 1964 and 1966, Bell traveled abroad, working and studying at the Mathematics Institute of Amsterdam, the University of Madrid (Spain), the University of Vienna (Austria), the Institute of Statistics at the University of Paris (France), and the University of Erlangen (West Germany).  During that time he also attended the International Mathematics Conference in Moscow, then capital of the Soviet Union.

From 1966 to 1981, Bell taught in succession at Case Western University, the University of Michigan at Ann Arbor, and the University of Washington at Seattle before returning to San Diego State University in 1981. He retired as full professor in 1992. Bell published nearly forty papers and was elected a Fellow in the Institute of Mathematical Statistics and the American Statistics Association. He also enjoyed traveling to meet fellow mathematicians in Africa, India, and Europe and welcomed the opportunity to hone his language skills in foreign countries. He once told an interviewer: “I enjoy family, I enjoy eating gumbo, and for more than four decades I enjoyed teaching mathematics and statistics and doing research in nonparametric statistics, stochastic processes and related problems and applications.” Bell’s other areas of expertise were biostatistics and signal detection which had highly sensitive military implications.

Charles B. Bell died in Los Angeles, California on October 26, 2010 at the age of 82. *Black Past




1957 Sir Simon Kirwan Donaldson FRS (born 20 August 1957) is an English mathematician known for his work on the topology of smooth (differentiable) four-dimensional manifolds, Donaldson–Thomas theory, and his contributions to Kähler geometry. *WikHe 
received a Fields Medal for his work on 4 dimensional manifolds. He was knighted in 2012 and awarded the most prestigious mathematical prizes including the Shaw Prize, the Breakthrough Prize in Mathematics, the Oswald Veblen Prize, and the Wolf Prize in Mathematics. *Wik 




1957 Sir Simon Kirwan Donaldson FRS (born 20 August 1957 Cambridge, England - ) In 1986 he received a Fields Medal for his work on the topology of four-manifolds. *VFR Remarkably, Donaldson has solved problems of mathematics by using ideas from physics. From the Yang-Mills generalizations of James Clerk Maxwell's electromagnetic equations, Donaldson used special solutions to these equations, called instantons, to look at general four-manifolds. After being awarded the Fields Medal, Donaldson continued his exploitation of ideas from physics with applications to mathematics. *TIS





DEATHS

1622 Baha ad-din Muhammad ibn Husayn al-Amili (20 Mar 1546; 20 Aug 1622 at age 76) A Syrian-Iranian theologian, mathematician and astronomer, a.k.a. Shaykh Baha'i). He became a very learned Muslim whose genius touched every field of knowledge from mathematics and philosophy to architecture and landscape design. He revived the study of mathematics in Iran. His treatise on the subject, Khulasat al-hisab (“The Essentials of Arithmetic”), and translations from the original Arabic was in use as a textbook until the end of the 19th century. His treatise in astronomy, Tashrihu'l-aflak ("Anatomy of the Heavens") summarised the works of earlier masters. He was born within a year of William Gilbert in England and Tycho Brahe in Denmark, and was still a child when his family left Syria to escape religious persecution.*TIS




1672 Jan de Witt (September 24, 1625, Dordrecht - August 20, 1672) murdered by a mob from the (William of) Orange faction. For the previous twenty years he served as grand pensionary in Holland, essentially the prime minister of the Netherlands. Consequently this talented mathematician had little time to devote to mathematics. He wrote the first systematic account of the analytic geometry of the straight line and conics. It was published in Van Schooten’s second Latin edition of Descartes’ Geometrie *VFR de Witt and his brother were both killed by a mob which was probably supported by William III of Orange. At the very least, as the Wikipedia articles states, "he protected and rewarded the killers." After a previous attempt on his life, he was lured by a forged letter to the cell where his brother was held, and both were hanged and then their bodies were mutilated. The story of their deaths are a critical element in the plot of Alexander Dumas' "The Black Tulip". *Wik




1677 Pierre Petit (8 Dec 1594 in Montluçon, France - 20 Aug 1677 in Lagny-sur-Marne, France) was a French scientist who had a strong influence on the French government. He was one of Mersenne's collaborators. Petit was an influential figure with important government positions which enabled him to try to influence national science policy. A firm believer, as were the other members of Mersenne's group, of the experimental method rather than the philosophical approach advocated by Descartes, Petit argued strongly for better astronomical facilities in France. He wanted the King to establish a Royal Observatory to allow France to again take a leading role in astronomy. Petit argued that France had fallen behind some other European countries and was relying on observations made in other countries. Petit himself had a fine collection of astronomical instruments and several of these were of his own invention. In particular, late in his life, Petit devised a filar micrometer to measure the diameters of celestial objects such as the Sun, Moon and planets.*SAU




1791 Jacques Charles, (probably 1752 Cluny, Burgundy; August 20, 1791) Mathematician, born in Cluny, France. He is often confused with the Jacques A. C. Charles who is credited (or mis-credited) with Charles' Law and much of the work of this Jacques Charles. During the Late 18th Century both were active in Paris scientific circles and both were members of the Paris Scientific Academy. They were often distinguished by calling this one Charles the Geometer, and the other Charles the Balloonist since JAC Charles was active in promoting the use of hydrogen balloons and had designed the first balloon that is known to have been used.
This Jacques Charles is also frequently referred to by the historians who are aware of the confusion between them as Charles the Obscure.
Jacques Charles first contact with the Paris Acad of Sci was in a 1770 letter in which he submitted an article on a problem in Algebra at about the age of 18. It was turned down by the academy due to it's elementary level. The address shows that he was living in Cluny at the time. But two years later a second correspondence to the academy is read to the Academy, and Lavosier's minutes list his position as a professor of Mathematics as the school at Nanterre, on the outskirts of Paris. It is suspected that this was a preparatory school for young nobles who were training to become engineers that had been located there since the 1760's.
Between 1779 and 1785 Jacques Charles submitted seven articles to the Paris Academy, all of which were deemed worthy of publication, but only the last seemed to merit his admittance to this esteemed group. Condorcet, who was then perpetual secretary of the Academy said that this, as well as his prior papers certainly warranted his admission. It seems that Laplace, who had a conflict with Charles' mentor/sponsor, Bossut, and had been blocking his entry. With some behind the scenes effort by Lavosier had created a new geometry section, he was voted into the Academy on May 11 (often given as May 12).
By 1792 due to the confusion of their names, much of the mathematical work of Charles the Geometer would be credited to Charles the Balloonist and the "Geometer" would become the "obscure". Even the energetic J. C. Poggendorf would miscredit eight papers by the geometer to the other, and in biographies of J. A. C. Charles written even in the 20th century, you will see him credited as a "mathematician" and statements that suggest that "most of his writings were in mathematics." J. B. Gough, writing in an article in Isis in 1979 describes the ballooning Charles as, "nearly a mathematical illiterate."
The confusion between the two men of common names was exacerbated by the timing of this Charles' death. The year 1791 and the problems related to the Revolution made this the Academy of Sciences did not publish a Memoires, and as a result, no eloge's for the members who died in that year. Strangely, this was still four years before the better remembered Charles was admitted to the Academy.
He was buried (according to an old note to Cvomptes Rendes) at St. Germain l'auxerrois, but this seems hard to confirm in the church records. (*J. B. Gough)
Charles was also the Royal Professor of Hydrodynamics, and as such was also inducted into The Academy of Architecture. *Roger Hahn, More Light on Charles the Obscure, Isis, Vol. 72, No. 1 (Mar., 1981), pp. 83-86



1923 Vilfredo Pareto (15 Jul 1848, 20 Aug 1923) Italian economist and sociologist, known for his application of mathematics to economic analysis and for his theory of the 'circulation of elites'. His initial five-year course in civil engineering, graduating in 1870, gave him a grounding in mathematics. While working as an engineer, he studied philosophy and politics and wrote many periodical articles in which he was one of the first to analyse economic problems with mathematical tools. Pareto's first work, Cours d'economie politique (1896-97), included his famous 'law' of income distribution, a complicated mathematical formulation attempting to prove the distribution of incomes and wealth in society is not random and that a consistent pattern appears throughout history, in all parts of the world and in all societies. *TIS Pareto's Law was not created by him, but named in honor of him. The Pareto principle (also known as the 80-20 rule, the law of the vital few, and the principle of factor sparsity) states that, for many events, roughly 80% of the effects come from 20% of the causes.
(From my personal experience using statistics in Quality Engineering, this one rule of thumb is the single most important idea of all the things you learn.)
Business-management consultant Joseph M. Juran suggested the principle and named it after Pareto, who had observed in 1906 that 80% of the land in Italy was owned by 20% of the population; he developed the principle by observing that 20% of the pea pods in his garden contained 80% of the peas. *Wik




1930 Herbert Hall Turner (13 Aug 1861, 20 Aug 1930) English astronomer who pioneered many of the procedures now universally employed in determining stellar positions from astronomical photographs. After serving as chief assistant at the Royal Greenwich Observatory for nine years, he spent most of his career as Savilian professor of astronomy at Oxford University. One of the leaders in the worldwide effort to produce an astrographic chart of the sky, he developed improved methods for obtaining both positions and magnitudes from photographic plates. Most of his later work was in seismology; he compiled and published worldwide earthquake data starting in 1918, and he discovered the existence of deep-focus earthquakes in 1922. *TIS




1972 Carol (Vander Velde)Karp (10 August 1926, Forest Grove, Ottawa County, Michigan – 20 August 1972, Maryland) died of breast cancer. At the time she was at the height of her career in logic. She received her Ph.D. in 1959 from Southern California under the direction of Leon Henkin. She created the field of Infinitary Logics which studies logics such as Lω,ω which allowed for the conjunction and disjunction of countably many formulas. This work has become very important in modern logic. *VFR




2001 Sir Fred Hoyle (24 June 1915, 20 Aug 2001) English mathematician and astronomer, best known as the foremost proponent and defender of the steady-state theory of the universe. This theory holds both that the universe is expanding and that matter is being continuously created to keep the mean density of matter in space constant. He became Britain's best-known astronomer in 1950 with his broadcast lectures on The Nature of the Universe, and he recalled coining the term "Big Bang" in the last of those talks. Although over time, belief in a "steady state" universe as Hoyle had proposed was shared by fewer and fewer scientists because of new discoveries, Hoyle never accepted the now most popular "Big Bang" theory for the origin of the universe. *TIS
When  Willy Fowler, who was 72 years old at the time, was told he would share the Nobel  prize with Indian astrophysicist Subrahmanyan Chandrasekhar, who had carried out pioneering work on the structure of stars he was shocked.  Of Fowler's own close collaborator, Fred Hoyle – the British scientist who had led their joint research work – there was no mention.
Scientists' dismay at the refusal to give Hoyle a Nobel prize is understandable, although it should be noted that he could be cantankerous and opinionated and had offended a large number of influential colleagues unused to his Yorkshire bluntness. He had called some of them liars and cheats in public, while his beliefs, in later life, verged on the lunatic. He said Earth was being constantly bombarded by microbes from outer space and that these were responsible for outbreaks of flu and other illnesses. He also claimed that remains of archaeopteryx – the British Museum fossil that demonstrates the early link between dinosaurs and birds – was a fake. Such notions went down badly in scientific circles.




2006 Professor William (Bill) Parry FRS (3 July 1934–20 August 2006) was an English mathematician. During his research career, he was highly active in the study of dynamical systems, and, in particular, ergodic theory, and made significant contributions to these fields. He is considered to have been at the forefront of the introduction of ergodic theory to the United Kingdom. He played a founding role in the study of subshifts of finite type, and his work on nilflows was highly regarded.*Wik



2014 John Bryce McLeod, FRS FRSE (23 December 1929 – 20 August 2014) was a British mathematician, who worked on linear and nonlinear partial and ordinary differential equations.

Born in Aberdeen, Scotland, he was educated at Aberdeen Grammar School; the University of Aberdeen, where he took a first in Mathematics and Natural Philosophy in 1950; and Christ Church, Oxford, where he took a first in Mathematics in 1952. He was a Harmsworth Senior Scholar at Merton College, Oxford, from 1955 to 1956. He obtained his PhD in 1959 under the supervision of Edward Charles Titchmarsh at the University of Oxford.

He was a junior lecturer in Mathematics at the University of Oxford from 1956 to 1958, and a lecturer in mathematics at the University of Edinburgh from 1958 to 1960. He then returned to Oxford to take up a Fellowship in Pure Mathematics at Wadham College. He remained in Oxford until 1988, becoming a university lecturer in 1970, and a senior research fellow of the Science and Engineering Research Council from 1986 to 1991. In 1988 McLeod took up a professorship at the University of Pittsburgh, where he remained until his retirement in 2007.

McLeod married Eunice Third in 1956; they had three sons and a daughter. He died in England on 20 August 2014, aged 84





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

Wednesday, 19 August 2026

On This Day in Math - August 19

 



Let us weigh the gain and the loss in wagering that God is. Let us consider the two possibilities. If you gain, you gain all; if you lose, you lose nothing. Hesitate not, then, to wager that He is.

Blaise Pascal,Pensees (1670)

 The 231st day of the year; there are 231 cubic inches in a US Gallon, (admit it, you did NOT know that.)

 Ok, and it's also the sum of the squares of four distinct primes, 231 = 22 + 32 + 72 + 132.

 \((3!)^3 + (2!)^4 - (1!)^5 \) 231 = 12 + 23 + 34 + 45 + 56 + 61 (loop 1-2-3-4-5-6-1) 231 = 98 + 76 + 54 + 3 *Derek Orr

The prime factorization of 231 is 3 x 7 x 11, three primes in arithmetic progression.  There are only two year days with this quality, and 231 is the larger.  It was not until 1933 that a proof was found that there are infinitely many such arithmetic progressions.

Here are the seven partitions of  231 into strings of consecutive counting numbers  

231=1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21 231=10+11+12+13+14+15+16+17+18+19+20+21+22+23 231=16+17+18+19+20+21+22+23+24+25+26 231=30+31+32+33+34+35+36 231=36+37+38+39+40+41 231=76+77+78 231 =115+116
*Hansreudi Widmer

The sum of the first 21 integers, 231 is the 21st triangular number, It is also a hexagonal and an octahedral number.
*Wikipedia





EVENTS
1577 " On August 19, his new book is put to printing (one hundred copies) at John Day's press in Aldersgate. " The printing of John Dee's 'General and rare memorials...' begins.

ht  ‏@RCPmuseum

The Dee designed title page shows Elizabeth at the helm of #Britain’s imperial destiny.  HT Lunar Heritage
@Lunarheritage   
And more from *Lunar Heritage adding "Ist book to use the term 'BritishEmpire' it called for the 
creation of a ‘Pety-Navy-Royall’ to secure England’s growing colonial interests Dee dedicated it to
 a fellow close adviser of Elizabeth I, Christopher Hatton who co-funded Drake’s circumnavigation
 voyage of 1577-1580."


 

1758 
Etienne Montucla received the approval from the censors for his Histoire des mathematiques. Often called the first true history of mathematics. *VFR

His first volume focused primarily on Greek and Roman mathematics, while later editions (especially the expanded second edition, begun in the 1790s and completed posthumously by Jérôme Lalande) extended the scope to include Indian, Arabic, and contemporary European mathematics.

Montucla’s Histoire was groundbreaking because:

It treated mathematics as part of the broader intellectual and cultural history.

It emphasized continuity and the transmission of knowledge across civilizations.

It presented mathematics not just as a set of truths, but as a human endeavor evolving over time.
*PB notes

Because of its ambition and depth, Montucla’s work remained a standard reference for decades and helped establish the discipline of the history of mathematics as a legitimate scholarly field.
His first work was Histoire des recherches sur la quadrature du cercle which was published by Jombert in Paris in 1754, and the high regard in which this work was held can be judged by the fact that on the strength of this work alone Montucla was elected a corresponding member of the Berlin Academy. Although the history of the problem of squaring the circle has changed greatly since Montucla's day this book is still a classic of its kind. *SAU





1791 "On this day in 1791, Benjamin Banneker (free African American scientist & almanac author) published his 1st Almanac."*Bibliophilia ‏@Libroantiguo

He sent a copy to Thomas Jefferson, along with a famous letter challenging Jefferson’s views on race and slavery, arguing for the rights and potential of Black people.

His almanacs were published annually between 1792 and 1797, and they gained wide circulation in the Mid-Atlantic states.

This milestone is often cited as one of the earliest documented examples of scientific authorship and political advocacy by a free African American. *PBnotes




1819 the first bicycle in the U.S. were seen in New York City. Such bicycle velocipedes or "swift walkers" had been imported that same year. Shortly thereafter  on 19 Aug 1819, the city's Common Council passed a law to "prevent the use of velocipedes in the public places and on the sidewalks of the city of New York."*TIS (Skateborders take note, you are not the fiterrst to be banned from the sidewalks)





1877 Asaph Hall discovered Deimos on 12 August 1877 at about 07:48 UTC and Phobos on 18 August 1877, at the US Naval Observatory (the Old Naval Observatory in Foggy Bottom) in Washington,
After first observing the outer satellite of Mars on Aug 11, bad weather prohibited observations of the planet for several days.  While trying to verify the outer moon and record data, the inner moon was discovered on Aug 17.  On the 19th after confirming evidence of both moons, Admiral John Rogers,superintendent of the United States Naval Observatory,announced to the World that Mars had two moons. *PBallew notes.

 See my blog on Typing Monkeys for earlier mention of Mars having two moons 

In 1887, Dmitri Ivanovich Mendeleev (1834-1907) used a balloon to ascend above the cloud cover to an altitude of 11,500 feet (3.5 km) to observe an eclipse in Russia. He made the solo ascent above Klin without any prior experience. While his family was rather concerned, he paid no attention to controlling the balloon until after he had completed his observations, at which time he worked out how to land it. Mendeleev is the Russian chemist known for the ordering of the Periodic Table of the Elements. Yet, he was interested in many fields of science. He studied problems associated with Russia's natural resources, such as coal, salt, metals, and the petroleum industry. In 1876, he visited the U.S. to observe the Pennsylvania oil fields. *TIS 
Mendeleev, Alfred Werner, Adolf von Baeyer, and other prominent chemists at 1900 Anniversary of Berlin Academy




1888 Irving Stringham, after a few years at the newly formed University of California at Berkeley, writes Felix Klein, his old professor, to complain that, "I impatiently await the time when it will be possible to bring some important researchers in the field of mathematics to the California coast." *Karen Hunger Parshall, David E. Rowe; The Emergence of the American Mathematical Research Community, 1876-1900  
Stringham (December 10, 1847 – October 5, 1909) was an American mathematician born in Yorkshire, New York. He was the first person to denote the natural logarithm as 
ln(x) where 𝑥 is its argument. The use of ln(x) in place of log𝑒 (x)
is commonplace in digital calculators today.

In 1880 he was awarded a Parker Fellowship by Harvard and, funded by this, he went to Europe. In particular he spent time at Leipzig where he attended lectures by Felix Klein. He wrote in letters back to Daniel Coit Gilman, the president of Johns Hopkins, about attending weekly seminars:-
... with Professor Klein's wonderful critical faculty continually at play.

Stringham was an early influence in the geometry of the fourth dimension. Stringham published in 1880 in the American Journal of Mathematics an article containing one of the earliest known sets of illustrations of the projections on a plane of the six regular polyhedroids or polytopes — the four-dimensional counterparts of the five regular polyhedra: tetrahedron, octahedron, cube, icosahedron and dodecahedron. 

His image of the tesseract (a term Charles Hinton would create eight years later) was the common representation of the 4th dimensional analogy of a cube.







1995  Credit for first surfacing a rural U.S. public road with Portland Cement Concrete pavement is generally conceded to Wayne County, Michigan. A one-mile section of Woodward Avenue was opened on July 4th, 1909 . As shown in the painting, motorists, farmers, and others users seemed to approve.

Before preparing specifications, Wayne County commissioners visited Windsor, Ontario, Canada, the first North American city to pave streets extensively with Portland Cement Concrete.

The Wayne County "first" was also preceded by:

The Long Island Motor Parkway Company, which laid the first concrete pavement on a private right-of-way for an auto racing course in 1908.
Bellefontaine, Ohio's first concrete street pavement in the Western Hemisphere in 1891.
Connersville, Indiana's small stretch of concrete alley in 1890.
The earliest ever Portland Cement Concrete pavement is attributed to Inverness, Scotland, in 1865. Federal Hwy Admin .   

BUT


The fun began a little later, and still rolls down (and Up) Woodward Avenue to this day,,,,, they are dream cruising today.  
The first Woodward Dream Cruise took place on August 19, 1995.

It began as a small fundraising event organized by Nelda Jefferies to raise money for a soccer field in Ferndale, Michigan. The idea was to recreate the 1950s and 60s tradition of teenagers cruising up and down Woodward Avenue, a major thoroughfare in the Detroit area, in classic cars.

Expecting around 30,000 people, the event instead drew over 250,000 attendees, and its overwhelming success led to it becoming an annual tradition. Today, the Woodward Dream Cruise is the largest single-day car event in the world, attracting over a million visitors and tens of thousands of classic cars each August.
Woodward Avenue in Detroit is named after Augustus B. Woodward. Woodward also had a strong interest in science and education, and he is considered one of the founders of the University of Michigan. *PBnotes








BIRTHS




1584 Pierre Vernier born (19 August 1580 at Ornans, Franche-Comté, Spanish Habsburgs (now France) – 14 September 1637 same location). He developed an accurate scale for the astrolabe. The Vernier scale that he invented in 1631 is still common on precision instruments. First described in English by John Barrow in 1750 in his Navigatio Britannica. It is sometimes called a nonius after Pedro Nunes, the Portuguese mathematician and instrument maker, who designed a precursor to the vernier scale in 1542. A nice illustration of how the Vernier alignment method works is at this Wikipedia site. *WikClavius originated a way of dividing a scale for precise measurements. His idea was adopted by Vernier 42 years later.

1646 John Flamsteed (19 Aug 1646; 31 Dec 1719)English astronomer who established the Greenwich Observatory. Science Historian/blogger Thony Christie writes
"the observational astronomer John Flamsteed Observational astronomy only produced three significant star catalogues in the two thousand years leading up to the 18th century. The first, the Greek catalogue from Hipparchus and Ptolemaeus published by Ptolemaeus in the 2nd century CE, which contained just over 1000 stars mapped with an accuracy that was astounding for the conditions under which it was produced. The second, containing somewhat more that 700 stars plus another 300 borrowed from the Ptolemaeus catalogue, was produced by the Danish astronomer Tycho Brahe in the last quarter of the 16th century, with an accuracy many factors better than his Greek predecessors. Both of these catalogues were produced with naked eye observations. The first catalogue to be produced using telescopic sights on the measuring instruments was that of John Flamsteed published posthumously in 1725, which contains more than 3000 stars measured to a much higher degree of accuracy than that of Tycho."
He then goes on to correct some misconceptions about Flamsteed's life that are commonly repeated, (he did NOT take part in talking Charles II into creating the observatory) and gives a nice description of a complex man. *Renaissance Mathematicus

fig: Perseus and Andromeda constellations, from Flamstead's Atlas coelestis (1729)




1739 Georg Simon Klügel (August 19, 1739 – August 4, 1812) made an exceptional contribution to trigonometry, unifying formulae and introducing the concept of trigonometric function, in his Analytische Trigonometrie. Euler, who studied similar problems 9 years later, in some respects achieved less than Klügel in this area. Folta writes:"Klügel's trigonometry was very modern for its time and was exceptional among the contemporary textbooks. "
It was his mathematical dictionary, however, which led to his fame. This was a three volume work which appeared between 1803 and 1808. In 1808 Klügel became seriously ill and could do no further work on the project. Another three volumes were added between 1823 and 1836 by Mollweide and Grunert and the dictionary was widely used for several generations making Klügel's name widely known. *SAU



1790 Edward John Dent (19 Aug 1790 - 8 Mar 1853).English clockmaker and inventor whose chronometers were noted for high accuracy. His patents in this field included compasses for navigation and surveying. He experimented with springs made of steel, gold and glass, and devices for counteracting the effects of temperature change upon timepiece mechanisms. As clockmaker to Queen Victoria, he was commissioned to build the Great Clock for the clock tower of the Houses of Parliament (known as Big Ben, although that is actually the nickname of its hour bell) which he began in the year he died. His son, Frederick Dent, completed the work the following year and it was installed in the tower in 1859. It continues to be recognized for its great accuracy of 4 seconds in a year.*TIS




1830 (Julius) Lothar Meyer (19 Aug 1830; 12 Apr 1895) was a German chemist who discovered the Periodic Law, independently of Dmitry Mendeleyev, at about the same time (1869). However, he did not develop the periodic classification of the chemical elements as thoroughly as Mendeleyev. Meyer trained originally in medicine and chemistry. He examined the effect of carbon monoxide on blood. In 1879, Meyer compared atomic volume to atomic weight. Plotted on a graph, the curve showed the periodicity of the elements. He also established the concept of valency by indicating that a given element combined with a characteristic number of hydrogen atoms, and coined the terms like univalent, bivalent, and trivalent, based on that number.*TIS



1872 Théophile Ernest de Donder (19 August 1872 – 11 May 1957) was a Belgian mathematician and physicist famous for his 1923 work in developing correlations between the Newtonian concept of chemical affinity and the Gibbsian concept of free energy.
He received his doctorate in physics and mathematics from the Université Libre de Bruxelles in 1899, for a thesis entitled Sur la Théorie des Invariants Intégraux (On the Theory of Integral Invariants).
He was professor between 1911 and 1942, at the Université Libre de Bruxelles. Initially he continued the work of Henri Poincaré and Élie Cartan. As from 1914 he was influenced by the work of Albert Einstein and was an enthusiastic proponent of the theory of relativity. He gained significant reputation in 1923, when he developed his definition of chemical affinity. He pointed out a connection between the chemical affinity and the Gibbs free energy.
He is considered the father of thermodynamics of irreversible processes. De Donder’s work was later developed further by Ilya Prigogine. De Donder was an associate and friend of Albert Einstein. *Wik




1934 Chester Gordon Bell (August 19, 1934 – May 17, 2024) is born Digital Equipment Corporation​ (DEC) innovator . In his 23 years at DEC, Bell developed several of the company's most successful minicomputers as well as its well-known VAX machine. One the world's top computer architects, Bell is considered by many to be the father of the minicomputer and is also an authority on supercomputing. The author of several books, Bell's awards include the National Medal of Technology and the IEEE Von Neumann Medal. *CHM




1939 Alan Baker born in London Alan Baker FRS (19 August 1939 – 4 February 2018) In 1970 he received a Fields Medal for his work on Hilbert’s seventh problem which dealt with transcendental numbers. *VFR In mathematics, a transcendental number is a number (possibly a complex number) that is not algebraic—that is, it is not a root of a non-constant polynomial equation with rational coefficients. The most prominent examples of transcendental numbers are π and e. The word transcendental seems to have been created by Liebniz. In 1900, David Hilbert posed an influential question about transcendental numbers, Hilbert's seventh problem: If a is an algebraic number, that is not zero or one, and b is an irrational algebraic number, is ab necessarily transcendental? The affirmative answer was provided in 1934 by the Gelfond–Schneider theorem. This work was extended by Alan Baker in the 1960s in his work on lower bounds for linear forms in any number of logarithms (of algebraic numbers). *Wik




1973 Olga Holtz (August 19, 1973 - ) is a Russian mathematician specializing in numerical analysis. She received the Sofia Kovalevskaya Award in 2006 and the European Mathematical Society Prize (2008). Since 2008, she is a member of the Young Academy of Germany.

Holtz's early mathematical development was largely due to her parents, who were both programmers.

After winning a €1,000,000 Sofia Kovalevskaya Award in 2006, Holtz built her research group at the Technical University Berlin, [ where she became a Professor of applied mathematics while concurrently serving as an Associate, then Full Professor of Mathematics at University of California, Berkeley. Since then, Holtz has garnered additional honors. The European Mathematical Society awarded her its 2008 prize, and the European Research Council awarded her €880,000 Starting Grant in August 2010. In 2015 she was elected as a fellow of the American Mathematical Society "for contributions to numerical linear algebra, numerical analysis, approximation theory, theoretical computer science, and algebra".

Holtz, who considered a career in music before deciding on mathematics, performs with the Berlin Philharmonic Choir and practices ballroom dancing, (in her spare time????)*Wik 
Holtz at the Institute for Advanced Study in Princeton, October 2009

*Wik





DEATHS

1662 Blaise Pascal died (19 June 1623 – 19 August 1662). I can not be brief about a life that contained so much in such a short time, so I mention his death. Sickly for most of his life (autopsies showed he had a deformed skull), he grew much worse in 1662. Pascal was also in a severe depression after his sister's death the year. On the night before his death he went into convulsions and received the sacraments. His last words were "May God never abandon me." He was thirty-nine years old at the time of his death. He is buried in the cemetery of Saint-Étienne, the little church where he worshiped regularly in the fifth district of Paris, near the Parthenon. There is a simple small marker near the front of the church. While frequently overlooked today, it was a prestigious church during Pascal's life. *Wik Among Pascal's lesser known inventions, it seems that he may have established the first commercial bus line in Paris.  The profits were all to go to the monastery in Port Royal.*Peter L. Bernstein, Against the Gods


 Blaise and I at the Louvre considering the roulette




1703 John Wallis (23 Nov 1616, 19 Aug 1703) British mathematician who introduced the infinity math symbol. Wallis was skilled in cryptography and decoded Royalist messages for the Parliamentarians during the Civil War. Subsequently, he was appointed to the Savilian Chair of geometry at Oxford in 1649, a position he held until his death more than 50 years later. Wallis was part of a group interested in natural and experimental science which became the Royal Society, so Wallis is a founder member of the Royal Society and one of its first Fellows. Wallis contributed substantially to the origins of calculus and was the most influential English mathematician before Newton. *TIS In addition to the infinity sign, and the use of it's reciprocal for infinitesimals, he also is credited with the idea of number line. He also probably originated the terms "mantissa" and "continued fraction". The commonly repeated idea that he refused to believe negative numbers were "less than zero" is dispelled by his use of the number line to show 5 - 8 = -3 in his "Treatise on Algebra", in 1685. *personal correspondence from Professor Phillip Beeley, Wallis Project, Oxford Univ.




1822 Jean Baptiste Joseph chevalier Delambre (19 September 1749, Amiens – 19 August 1822, Paris) was a French mathematician and astronomer. He was also director of the Paris Observatory, and author of well-known books on the history of astronomy from ancient times to the 18th century. Delambre was one of the first astronomers to derive astronomical equations from analytical formulas. His name is also one of the 72 names inscribed on the Eiffel tower. Delambre died in 1822 and was interred in the Père Lachaise Cemetery in Paris.




1887 Alvan Clark (8 Mar 1804, 19 Aug 1887)American astronomer whose family became the first significant manufacturers of astronomical instruments in the U.S. His company manufactured apparatus for most American observatories of the era, including Lick and Pulkovo, and others in Europe. In 1862, while testing a telescope, Clark discovered the companion star to Sirius, which had previously been predicted but until then never sighted. The 18½-in objective telescope he used was subsequently delivered to the Dearborn Observatory, Chicago. His sons, Alvan Graham Clark and George Bassett Clark, continued the business. The unexcelled 40-in refractor telescopes for the 40-in Yerkes observatory was made by Alvan Graham Clark*TIS




1910 Eugène Rouché (18 August 1832 at Sommières, Hérault, France - 19 August 1910 at Lunel, Hérault) died on the day following his seventy-eighth birthday. A French Geometer who edited Laguerre's "Collected Works". He also is known for Rouche's Theorem on Complex functions. *SAU





1957 Maurice Kraitchik (April 21, 1882, Minsk - August 19, 1957, Bruxelles) was a Belgian mathematician, author, and game designer. His main interests were the theory of numbers and recreational mathematics.
He is famous for having inspired the two envelopes problem in 1953, with the following puzzle in La mathématique des jeux:
Two people, equally rich, meet to compare the contents of their wallets. Each is ignorant of the contents of the two wallets. The game is as follows: whoever has the least money receives the contents of the wallet of the other (in the case where the amounts are equal, nothing happens). One of the two men can reason: "Suppose that I have the amount A in my wallet. That's the maximum that I could lose. If I win (probability 0.5), the amount that I'll have in my possession at the end of the game will be more than 2A. Therefore the game is favorable to me." The other man can reason in exactly the same way. In fact, by symmetry, the game is fair. Where is the mistake in the reasoning of each man?

Kraitchik wrote several books on number theory during 1922-1930 and after the war, and from 1931 to 1939 edited Sphinx, a periodical devoted to recreational mathematics.

Kraitchik coined the word automorphic numbers for numbers like 5 and 6 that repeat the original number at the end of squaring,   thus 25^2 =625 and 376^2 = 141376.  In 1942 he introduced the term cryptarithmetic for problems like the well known SEND + MORE = MONEY.

During World War II, Kraïtchik emigrated to the United States, where he taught a course at the New School for Social Research in New York City on the general topic of "mathematical recreations." *Wik




1957 Carl-Gustaf Arvid Rossby (28 Dec 1898, 19 Aug 1957) Swedish-U.S. meteorologist who first explained the large-scale motions of the atmosphere in terms of fluid mechanics. His work contributed to developing meteorology as a science. Rossby first theorized about the existence of the jet stream in 1939, and that it governs the easterly movement of most weather. U.S. Army Air Corps pilots flying B-29 bombing missions across the Pacific Ocean during World War II proved the jet stream's existence. The pilots found that when they flew from east to west, they experienced slower arrival times and fuel shortage problems. When flying from west to east, however, they found the opposite to be true. Rossby created mathematical models (Rossby equations) for computerized weather prediction (1950).*TIS

1964 Hugo Gernsback (August 16, 1884 – August 19, 1967), born Hugo Gernsbacher, was a Luxembourgish-American inventor, writer, editor, and magazine publisher, best known for publications including the first science fiction magazine. His contributions to the genre as publisher were so significant that, along with the novelists H. G. Wells and Jules Verne, he is sometimes called "The Father of Science Fiction". In his honour, annual awards presented at the World Science Fiction Convention are named the "Hugos" *Wik




1968 George Gamow (4 Mar 1904,19 Aug 1968) Russian-born American nuclear physicist, cosmologist and writer who was one of the foremost advocates of the big-bang theory, which desribes the origin of the universe as a colossal explosion that took place billions of years ago. In 1954, he expanded his interests into biochemistry and his work on deoxyribonucleic acid (DNA) made a basic contribution to modern genetic theory. *TIS
Einstein is often quoted as saying that his use of a "cosmological constant" in his equations for the General Theory of Relativity was his "greatest blunder".  Recently (2013) I read that Mario Livio suspected that the quote had been made up by Gamow and first appears in a Scientific American article in 1956.  He quotes Gamow's history of "antics" and a quote from his wife that  ""In more than twenty years together, Geo has never been happier than when perpetuating a practical joke." *Rebecca J Rosen, The Atlantic



1983 Octav Onicescu (Romanian pronunciation: [ August 20, 1892 – August 19, 1983) was a Romanian mathematician and a member of the Romanian Academy. Together with his student, Gheorghe Mihoc, he is considered to be the founder of the Romanian school of probability theory and statistics.
Onicescu was one of the founders of the Balkan Union of Mathematicians (in 1934) and of the International Centre for Mechanical Sciences in Udine (in 1968).

The "Octav Onicescu" museum, founded in Botoșani in October 1995, houses furniture and memorabilia that belonged to him, including manuscripts, letters, diplomas, books, photographs, and military decorations. The memorial house doesn't exist anymore.

Oniscescu defined and studied the information energy and correlation coefficient in information theory.*Wik




1990  Leifur Ásgeirsson (25 May 1903 – 19 August 1990) was the first Icelandic mathematician to gain major international recognition.
He graduated in 1927 from Reykjavik Junior College and received his doctorate in 1933 from the University of Göttingen. His doctoral advisor was Richard Courant. From 1931 to 1943 Leifur Ásgeirsson was the head of a district school in Laugar, located in southwestern Iceland's Reykjadalur Valley east of Reykjavík. In 1936 he was an invited speaker at the International Congress of Mathematicians in Oslo. At the University of Iceland he was appointed in 1943 a lecturer in mathematics and in 1945 a full professor of mathematics.





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