Sunday, 14 December 2025

An 18th Century quick Approximation for Angles in Right Triangle (Repost)

  





The triangle above is a right triangle, and almost no one who reads this blog didn't know that. In fact for most people who have had a pretty good math background, you would be surprised to read a property or theorem about right triangles that you didn't know, or at least hadn't heard, especially if it dates back to the 18th Century.

Ok, so if I give you the three side lengths of a right triangle, how would you find the smallest angle..... Hold on, No calculator, and No tables...
I had no idea how to achieve such a result when I came across such a method by a Hugh Worthington in "An essay on the Resolution of Plain Triangles, by Common Arithmetic." It was in an anthology of math writing from the 1500's to the present in "A Wealth of Numbers: An Anthology of 500 Years of Popular Mathematics Writing" by Benjamin Wardhaugh (pg 97), credited to Hugh Worthington in 1780.


So How is it done? Well, in the words of the author, "half the longer of the two legs added to the hypotenuse, is always in proportion to 86 as the shorter leg is to its opposite angle. "

As a math equation we with c as the hypotenuse and a as the smallest leg, he states that \(\frac{b/2+c}{86}=\frac{a}{A}\)

In the common 3,4,5 triangle that produces \(\frac{7}{86}=\frac{3}{A}\) and A would be equal to 36.85714286 (Ok, I divided it out on my calculator). Then I checked using Arcsin(3/5) and got 36.86989765...... OK, That seems to be a really good approximation, and I checked with a much smaller angle (the 7, 24, 25 triangle) and it was also very close.

I've been working on this for a while and can't come up with how he might have arrived at this approximation, nor can I find any other use of this. Would love to know if it was explained somewhere, or other works using it.

Addendum: Some really good math in the comments leading to the idea from Matt McIrvin and Paul Hertzer that "I think the leading error in this rule actually comes from the use of 86 degrees as an approximation to 1.5 radians." So using 85.94 or so as the constant improves the already awesome (my view) approximation accuracy. Thanks guys.. now can anybody find another publication using this idea?

Shortly after I wrote this, John Golden, an amazing teacher of math educators created a geogebra demo to greatly improve this, so I immediately stole it and added it here. Thanks John.


On This Day in Math - December 14

  


Those who study the stars have God for a teacher.

~Tycho Brahe


The 348th day of the year; 348 is the sum of four consecutive primes. It is the last day of the year that is of such distinction.

348 is the smallest number whose fifth power contains exactly the same digits as another fifth power... find it.

348 is a practical number because any smaller number is the sum of distinct divisors of 348. Only three larger year days have that quality.




EVENTS


1498 Luca Pacioli was professor in Milan 1496-1499. He was inspired to start his Divina Proportione on 9 Feb 1498 and completed it on 14 Dec 1498, though it was not published (in an expanded form) until 1509 . The period in Milan was the high point of his career, being a leading member of the glittering intellectual court of Lodovico Sforza. He lived at the monastery of San Simpliciano, writing his Divina Proportione, and De Viribus Quantitatis here . He was a good friend of LEONARDO DA VINCI who drew the pictures for Pacioli's book. Pacioli is our leading witness to Leonardo's work at this time, particularly the Last Supper in the Refectory of the Monastery of Santa Maria delle Grazie during 1495 1497, and he may well have advised on the perspective of the painting. Certainly Pacioli stimulated Leonardo's interest in perspective and it is possible that Leonardo's famous drawing of the proportions of the human body was inspired by Pacioli's comment on classical architecture; "For in the human body they found the two main figures ..., namely the perfect circle and the square." Pacioli seems to have made models of the polyhedra illustrated in his book, though we don't know if Leonardo used these for his drawings. A set was probably given to Pacioli's earlier patron, the Duke of Urbino, in 1494. Another set was paid for by Florence in 1504. *VFR

Luca Pacioli, born in 1445, was an influential Italian mathematician and Franciscan friar, known primarily for his significant contributions to accounting and bookkeeping. Often referred to as the “Father of Accounting,” Pacioli was an essential figure in the development and dissemination of mathematical knowledge during the Renaissance period.*PB

Divina proportione (written in Milan in 1496–1498, published in Venice in 1509). Two versions of the original manuscript are extant, one in the Biblioteca Ambrosiana in Milan, the other in the Bibliothèque Publique et Universitaire in Geneva. The subject was mathematical and artistic proportion, especially the mathematics of the golden ratio and its application in architecture. It incorporates without credit a translation of the entire book De quinque corporibus regularibus by Piero della Francesca.[9] Leonardo da Vinci drew the illustrations of the regular solids in Divina proportione while he lived with and took mathematics lessons from Pacioli. Leonardo's drawings are probably the first illustrations of skeletal solids, which allowed an easy distinction between front and back. The work also discusses the use of perspective by painters such as Piero della Francesca, Melozzo da Forlì, and Marco Palmezzano. *Wik

In the Portrait of Luca Pacioli , traditionally attributed to Jacopo de’ Barbari, the book that Pacioli is pointing toward is almost universally identified as Euclid’s Elements.

The first known printing of the Rhombicubeoctahedron, an Archimedian Solid with 26 faces, was Leonardo da Vinci's drawing in Divina Proportione


In 1807, the first meteorite strike to be recorded in the U.S. fell at Weston (now called Easton), Conn., at 6:30 a.m., making a hole 5-ft long and 4.5-ft wide. This was the New World's first witnessed fall of a meteorite, with subsequent recovery of specimens, since the arrival of the European settlers. Yale Professor Benjamin Silliman's description of the fall and his chemical analysis of the stone meteorite, the first performed in the U.S., received much attention in the national and international press. A thirty-pound fragment of this Chondrite H4 became the nucleus of Yale University’s Peabody Museum. This meteorite collection, the oldest in the country, was begun by Silliman.*TIS Eyewitnesses reported three loud explosions, and stone fragments fell in at least six locations. *Wik  

Out of the approximately 350 pounds of meteorite that fell on Weston in December 1807, fewer than 50 pounds can be accounted for today according to the Yale Peabody Museum of Natural History.

The Weston (above, YPM MIN 100375) and Wolcott (below, YPM MIN 100439) meteorites and Silliman’s 1810 article.




1844 Hermann Grassman had sent a copy of his book to Gauss who replied that a) I already did that fifty years ago, and b) I didn’t actually read it because I’m very busy and the terminology is difficult. Michael Crowe described Grassmann’s book, “Grassmann’s Die lineale Ausdehnungslehre (Linear Extension Theory) demonstrated deep mathematical insights. It also in one sense contained much of the modern system of vector analysis. This, however, was embedded within a far broader system, which included n-dimensional spaces and as many as sixteen different products of his base entities (including his inner and outer products, which are respectively somewhat close to the our modern dot and cross products). Moreover, Grassmann justifies his system by philosophical discussions that may have put off many of his readers.” *A history of vector analysis: the evolution of the idea of a vectorial system, By Michael J. Crowe pg 78




1893 The American, Dorothea Klumpke defended her thesis on Saturn’s rings for a doctorate in mathematics at the Sorbonne, before an expectant gathering of professors and several hundred spectators. “Your thesis,” said one of the examining professors during the awards ceremony, “is the first which a woman has presented and successfully sustained with our faculty to obtain this degree. You worthily open the way.” Indeed she did, for she became a distinguished astronomer. *Sky & Telescope, August 1986, pp. 109–110. Reprinted in AWM Newsletter, 17, no. 5, p. 12-13.

She was the Director of the Bureau of Measurements at the Paris Observatory and was made a Chevalier de la Légion d'Honneur, or a Knight of the National Order of the Legion of Honor.




In 1900, German physicist Max Planck made public his ideas on quantum physics at a meeting of the German Physics Society, revolutionizing scientists' understanding of physics. Planck demonstrated that in certain situations energy exhibits characteristics of physical matter, something unthinkable at the time. He suggested the explanation energy exists in discrete packets, which he called "quanta."*TIS

Planck's first proposed solution to the problem in 1899 followed from what he called the "principle of elementary disorder", which allowed him to derive Wien's law from a number of assumptions about the entropy of an ideal oscillator, creating what was referred to as the Wien–Planck law. Soon, however, it was found that experimental evidence did not confirm the new law at all, to Planck's frustration. He revised his approach and now derived the first version of the famous Planck black-body radiation law, which described clearly the experimentally observed black-body spectrum. It was first proposed in a meeting of the DPG on 19 October 1900 and published in 1901. (This first derivation did not include energy quantisation, and did not use statistical mechanics, to which he held an aversion.) In November 1900 Planck revised this first version, now relying on Boltzmann's statistical interpretation of the second law of thermodynamics as a way of gaining a more fundamental understanding of the principles behind his radiation law. Planck was deeply suspicious of the philosophical and physical implications of such an interpretation of Boltzmann's approach; thus his recourse to them was, as he later put it, "an act of despair ... I was ready to sacrifice any of my previous convictions about physics".[


The central assumption behind his new derivation, presented to the DPG on 14 December 1900, was the supposition, now known as the Planck postulate, that electromagnetic energy could be emitted only in quantized form, in other words, the energy could only be a multiple of an elementary unit: E=hv  *Wik




1911 “So we arrived and were able to plant our flag at the geographical South Pole. God be thanked!” From the diary of the Norwegian explorer, Roald Amundsen, the first person to reach the South Pole. He was accompanied by four companions and fifty-two sled dogs. *VFR


In 1933, Rutherford suggested the names diplogen for the newly discovered heavy hydrogen isotope and diplon for its nucleus. He presented these ideas in the Discussion on Heavy Hydrogen at the Royal Society. For ordinary hydrogen, the lightest of the atoms, having a nucleus of a sole proton, he coined a related name: haplogen. (Greek: haploos, single; diploos, double.) In 1931, Harold Urey had discovered small quantities of atoms of heavy hydrogen wherever ordinary hydrogen occurred. The mass of its nucleus was double that of ordinary hydrogen. This hydrogen-2 is now called deuterium, as named by Urey (Greek: deuteros, second). Its nucleus, named a deuteron, has a neutron in addition to a proton. *TIS 




1946 Denmark issued a stamp commemorating the 400th anniversary of the birth of the mathematician and astronomer Tycho Brahe. [Scott #300]. (TOP)*VFR

See Top


1981 The New Yorker carried a long interview with Marvin Minsky, tracing his biography and the development of artificial intelligence. [Mathematics Magazine 55(1982), p. 245]. *VFR


1952 U.S. Navy Approaches MIT to create Whirlwind
U.S. Navy issues a formal Letter of Intent to MIT for development of the Airplane Stability and Control Analyzer (ASCA) program, the beginning of the project Whirlwind. Constructed under the leadership of Jay. W. Forrester, the Whirlwind was the first high-speed electronic digital computer that was able to operate in real time with the remarkable electronic reliability. By December 1954, the computer comprised 12,500 vacuum tubes and 23,800 crystal diodes, occupying a two-story building. It operated until 1959.
Whirlwind served as an experimental prototype for the IBM’s AN/FSQ-7 manufactured for the SAGE air defense system, and influenced the early IBM 700 series computers and computers developed by Digital Equipment Corporation. 

In 1954  Edward R. Murrow’s See It Now program featured the Whirlwind computer.  The computer was noted for its reliability: it had the capability to run 35 hours a week at 90-percent utility using an electrostatic tube memory (Williams Tube). *CHM




In 1967, the first synthesis of biologically active DNA in a test tube was announced at a press conference by Arthur Kornberg who had worked with Mehran Goulian at Stanford and Robert L. Sinsheimer of MIT. Kornberg chose to replicate the relatively simple DNA chain of the Phi X174 virus, which infects bacteria (a bacteriophage). It has a single strand of DNA only about 5500 nucleotide building blocks long, and with about 11 genes, it was easier to purify without breaking it up. Having isolated the Phi X174 DNA, they used the DNA from E. coli, a common bacterium in the human intestine that could copy a DNA template from any organism. The viral DNA template thus copied was found to be able to infect bacteria - it was error-free, active DNA. *TIS


2009 On 14 December 2009, the Orient Express ceased to operate and the route disappeared from European railway timetables, reportedly a "victim of high-speed trains and cut-rate airlines" *Wik


2023. The annual Geminids meteor shower, which streaks across the night sky every year in mid-December, will peak on Tuesday night and into Wednesday..  The best time to watch is after midnight through dawn on December 14. 
The meteors will appear to radiate from a point near the star Castor, in the constellation Gemini.

 Under a dark sky with no moon, you might catch 120 Geminid meteors per hour.






BIRTHS


1503 The astrologer Nostradamus is born. [Muller] *VFR


1546 Tycho Brahe (14 Dec 1546; 24 Oct 1601) Danish astronomer whose work in developing astronomical instruments and in measuring and fixing the positions of stars paved the way for future discoveries. He studied the nova of 1572 ("Tycho's star") showed that it was a fixed star. His report, De nova...stella (1573), was taken by many as proof of the inadequacy of the traditional Aristotelian cosmology. In 1577, he moved to his own observatory on Hven Island (financed by King Frederick II). Before the invention of the telescope, using his nine-foot armillary sphere and his fourteen-foot mural quadrant, he charted the positions of 777 stars with an unparalleled accuracy. In 1599 he moved to Prague, with Johannes Kepler as his assistant. *TIS



1760 The Very Reverend James Wood (14 December 1760 – 23 April 1839) was a mathematician, Dean of Ely and Master of St John's College, Cambridge.
Wood was born in Holcombe where his father ran an evening school and taught his son the elements of arithmetic and algebra. From Bury Grammar School he proceeded to St John's College, Cambridge in 1778, graduating as senior wrangler in 1782. On graduating he became a fellow of the college and in his long tenure there produced several successful academic textbooks for students of mathematics. (The Elements of Algebra (1795); The Principles of Mechanics (1796); The Elements of Optics (1798))
Wood remained for sixty years at St. John's, serving as both President (1802–1815) and Master (1815–1839); on his death in 1839 he was interred in the college chapel and bequeathed his extensive library to the college, comprising almost 4,500 printed books on classics, history, mathematics, theology and travel, dating from the 17th to the 19th centuries.
Wood was also ordained as a priest in 1787 and served as Dean of Ely from 1820 until his death.{He was succeeded by another eminent mathematician, George Peacock)*Wik

On his death Wood bequeathed to the College his extensive library, comprising almost 4,500 printed books on classics, history, mathematics, theology and travel, dating from the 17th to the 19th centuries. Highlights include a copy of Erasmus’s Novum instrumentum omne (1516), Calvin’s Harmonia ex Evangelistis tribus composita (1572) in a contemporary binding, and Shelley’s The necessity of atheism (1811).





1904 Nikolai Grigor'evich Chudakov (December 14, 1904,–November 22, 1986) was a Russian and Soviet mathematician. He was born in Lysovsk, Novo-Burassk, Saratov, Russian Empire. His father worked as a medical assistant.
He first studied at the Faculty of Physics and Mathematics at Saratov State University, but then he transferred to Moscow University. He then graduated in 1927. In 1930, he was named head of higher mathematics at Saratov University. In 1936, he successfully defended his thesis and became a Doctor of Science. Among others, he considerably improved a result from Guido Hoheisel and Hans Heilbronn on an upper bound for prime gaps. *Wik



1914 Solomon Spiegelman (14 Dec 1914; 21 Jan 1983) American microbiologist and geneticist who discovered that only one of two strands of molecules that make up DNA, carried the genetic information to produce new substances. The carrier was called ribonucleic acid (RNA). In 1962, he developed a technique that allowed the detection of specific RNA and DNA molecules in cells. This technique, called nucleic acid hybridization, is credited for helping to lay the groundwork for current advances in recombinant DNA technology. Much earlier, his Ph.D. thesis (1944) was the first work to establish that genes are activated and deactivated by compounds that he called inducers, which thus radically affect the pattern of proteins that a cell fabricates without actually altering the genes themselves. *TIS




1922 Nikolay Gennadiyevich Basov (14 December, 1922 – 1 July, 2001 )Soviet physicist, best known for the development of the maser, the precursor of the laser. In 1955, while working as a research student with Aleksandr Prokhorov (1916- ) at the Soviet Academy of Sciences, he devised a microwave amplifier based on ammonia molecules. The two scientists shared the 1964 Nobel Prize (with American Charles Townes (1915- ), who independently developed a maser), for basic research in quantum electronics that led to the development of both the maser and the laser. These devices produce monochromatic, parallel, coherent beams of microwaves and light, respectively. Basov went on to develop the laser principle, and introduced the idea of using semiconductors to achieve laser action (1958). *TIS


Basov top and Townes MASER below





1936 Charles Terence Clegg ("Terry") Wall (born 14 December 1936 in Bristol, England) is a leading British mathematician, educated at Marlborough and Trinity College, Cambridge. He is an emeritus professor of the University of Liverpool, where he was first appointed Professor in 1965. From 1978 to 1980 he was the President of the London Mathematical Society.
His early work was in cobordism theory in algebraic topology; this includes his 1959 Cambridge Ph.D thesis entitled "Algebraic aspects of cobordism", written under the direction of Frank Adams and Christopher Zeeman. His research was then mainly in the area of manifolds, particularly geometric topology and related abstract algebra included in surgery theory, of which he was one of the founders. His 1970 research monograph "Surgery on Compact Manifolds" is a major reference work in geometric topology.
In 1971 he conjectured that every finitely generated group is accessible. This conjecture is known as "Wall's conjecture". It motivated much progress in the understanding of splittings of groups. In 1985 Martin J. Dunwoody proved the conjecture for the class of finitely presented groups. The resolution of the full conjecture took until 1991 when, surprising to most mathematicians at the time, Dunwoody found a finitely generated group that is not accessible and hence the conjecture turned out to be not correct in its general formulation.
C.T.C Wall's work since the mid-1970s has mostly been in singularity theory as developed by R. Thom, J. Milnor and V. Arnold, and especially concerns the classification of isolated singularities of differentiable maps and of algebraic varieties. He has written two research monographs on singularity theory, "The Geometry of Topological Stability" (1989) (containing a great deal of original work) with Andrew du Plessis, and "Singular Points of Plane Curves" (2004).*Wik



1938  David Breyer Singmaster (14 December 1938 – 13 February 2023) was an American-British mathematician who was emeritus professor of mathematics at London South Bank University, England. He had a huge personal collection of mechanical puzzles and books of brain teasers. He was most famous for being an early adopter and enthusiastic promoter of the Rubik's Cube. His Notes on Rubik's "Magic Cube" which he began compiling in 1979 provided the first mathematical analysis of the Cube as well as providing one of the first published solutions. The book contained his cube notation which allowed the recording of Rubik's Cube moves, and which quickly became the standard.

Singmaster was both a puzzle historian and a composer of puzzles, and many of his puzzles were published in newspapers and magazines. In combinatorial number theory, Singmaster's conjecture states that there is an upper bound on the number of times a number other than 1 can appear in Pascal's triangle.
Singmaster had one of the world's largest collections of books on recreational mathematics which he had accumulated starting in the late 1970s. In 1996 he reported that the collection contained over 4700 works. He also collected books on cartoons, humour, and language. In 2013 his book collection was reported to be "nearly 10000 items".







DEATHS


1710 Henry Aldrich (1647 – 14 December 1710) was an English theologian and philosopher.He had wide interests including mathematics, music, and architecture. He was well known as a humorist and Suttle describes him as".. a punner of the first value. "
In 1674 he published Elementa geometricae which led to him being described by his Christ Church colleagues as ".. a great mathematician of our house."
In 1691 he published Artis logicae compendium a treatise on logic which was to be the main text on the topic for 150 years in England. Even when Richard Whately published Elements of logic in 1826 it still took Aldrich's work as his starting point. *SAU




1897 Francesco Brioschi (22 December 1824 – 13 December 1897) was an Italian mathematician born in Milan in 1824. From 1850 he taught analytical mechanics in the University of Pavia. After the Italian unification in 1861, he was elected depute in the Parliament of Italy and then appointed twice secretary of the Education Minister. In 1863 he founded the Politecnico di Milano university, where he worked until death. In 1870 he became member of the National Academy of the Lincei and in 1884 he succeed Quintino Sella as president of the National Academy of the Lincei. He directed the Il Politecnico (English translation: The Polytechnic) review and, between 1867 and 1877, Annali di matematica pura e applicata (English translation: Annals of pure and applied mathematics). He died in Milan in 1897.
As mathematician, Brioschi publicized in Italy various algebraic theories and studied the problem of solving fifth and sixth grade equations using elliptic functions. Brioschi is also remembered as a distinguished teacher: among his students in the University of Pavia there were Eugenio Beltrami, Luigi Cremona and Felice Casorati.*Wik



1927 Yulian-Karl Vasilievich Sokhotsky (2 Feb 1842 in Warsaw, Poland - 14 Dec 1927 in Leningrad, USSR (now St Petersburg, Russia)) The magister's thesis of Sokhotskii was the first research paper on complex analysis published in Russian. It contains many important results which were later ascribed to other mathematicians. First of all, there is the famous theorem on the behaviour of an analytic function in a neighbourhood of an essential singularity. This theorem was published by Sokhotskii (in his magister's thesis) and by Casorati in 1868, whereas Weierstrass published it eight years later - in 1876. Furthermore, Sokhotskii was the first to apply the calculus of residues to Legendre polynomials. The credit for this procedure is usually given to Hermann Laurent. Finally, the so-called Plemelj formulas are also due to Sokhotskii, who published them in his doctor's thesis in 1873, that is to say 35 years before Plemelj. *SAU




1976 Donald H(oward) Menzel (11 Apr 1901, 14 Dec 1976) was an American astronomer best known for his arguments against the existence of extraterrestrial UFO's. Menzel was one of the first practitioners of theoretical astrophysics in the United States and pioneered the application of quantum mechanics to astronomical spectroscopy. An authority on the sun's chromosphere, he discovered with J. C. Boyce (1933) that the sun's corona contains oxygen. With W. W. Salisbury he made (1941) the first of the calculations that led to radio contact with the moon in 1946. He supervised the assignment of names to newly discovered lunar features. *TIS



1989 Andrey Dmitriyevich Sakharov (21 May 1921, 14 Dec 1989) Soviet nuclear physicist, an outspoken advocate of human rights in the Soviet Union. At the end of World War II, Sakharov returned to pure science and the study of cosmic rays. Two years later, he began work with a secret research group on the development of the hydrogen bomb, and he is believed to have been principally responsible for the Soviets' success in exploding their first thermonuclear bomb (1954). With I.E. Tamm, he proposed controlled thermonuclear fusion by confining an extremely hot ionized plasma in a torus-shaped magnetic bottle, known as a tokamak device. He became politically more active in the 1960s, campaigned against nuclear proliferation, and from 1980 to 1986, he was banished and kept under police surveillance.*TIS



2016 Jean-Paul Pier (July 5, 1933 – December 14, 2016) was a Luxembourgish mathematician, specializing in harmonic analysis and the history of mathematics, particularly mathematical analysis in the 20th century.

He taught mathematics at the Lycée de Garçons in Esch-sur-Alzette from 1956 to 1980. In 1971 he created the Séminaire de mathématiques at the Centre universitaire de Luxembourg (now the University of Luxembourg). He was a professor at the Centre from its creation in 1974 until 1998, when he retired as professor emeritus.

Pier was primarily responsible for the creation in January 1989 of the Luxembourg Mathematical Society, of which he was president from 1989 to 1993 and again from 1995 to 1998. He was during the academic year 1994–1995 a visiting professor at the Université catholique de Louvain.

Pier was the editor of two scholarly anthologies, which are standard works on the history of 20th-century mathematics. He organized several colloquia and conferences in Luxembourg. He was active internationally in various scientific bodies, including NATO Science for Peace and Security and UNESCO.





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

Saturday, 13 December 2025

Not Quite Equal

 




 ***** WARNING!!!!!********** Repeat of some very old jokes


Darryl Brock, A fellow teacher at school sent out some puns today... and I rewrote some of them as .... dare I call them... equations... 

 The roundest knight at King Arthur's round table = Sir Cumference.
 
 eye doctor on an Alaskan island =an optical Aleutian 

 A grenade thrown into a kitchen in France = Linoleum Blownapart 

 Atheism = a non-prophet organization

 A chicken crossing the road = poultry in motion 

 short fortune-teller who escaped from prison = a small medium at large

 WWI soldier who survived mustard gas and pepper spray = a seasoned veteran

cannibals eating a missionary = a taste of religion

 joining dangerous cults = Practicing un-safe sects!


*** Please do NOT throw things...  
But do send your examples of more of these...

On This Day in Math - December 13

  

Scottish Café (PolishKawiarnia Szkocka) in Lwów


Once a sage asked why scholars always flock to the doors of the rich, whilst the rich are not inclined to call at the doors of scholars. "The scholars" he answered, "are well aware of the use of money, but the rich are ignorant of the nobility of science".
al-Biruni


The 347th day of the year; 347 is a safe prime, one more than twice a Sophie Germain Prime, 173. There is only one more safe prime this year.
And from Derek at @MathYearRound, "Adding 2 to any digit of 347 keeps it prime (547, 367 and 349 are prime)."

Derek's comment also points out that 347 is the smaller of a pair of twin primes. I just found out that, "(p, p+2) are twin primes if and only if p + 2 can be represented as the sum of two primes. Brun (1919)" (Brun showed that even if there are an infinity of prime pairs, the sum of their reciprocals converges.)

There are 347 even digits before the 347th odd digit of π. (How often is it true that after 2n digits of π there are n even and n odd digits?)



Events


Not the Actual Aurora from 1128  ;-}

 1128 “In the third year of Lothar, emperor of the Romans, in the twenty-eighth year of King Henry of the English…on Saturday, 8 December, there appeared from the morning right up to the evening two black spheres against the sun.” This description of sunspots, and the earliest known drawing of sunspots, appears in John of Worcester’s Chronicle recorded in 1128. On the night of 13 December 1128, astronomers in Songdo, Korea, witnessed a red vapour that “soared and filled the sky” from the northwest to the southwest. A delay of five days is the average delay between the occurrence of a large sunspot group near the center of the Sun – exactly as witnessed by John of Worcester – and the appearance of the aurora borealis in the night sky at relatively low latitudes *Joe Hanson, itsokaytobesmart.com


 1743, On Dec 13, Jean-Philippe Loys de Cheseaux spotted a comet in the sky.  He was not the first to see the comet, having been preceded by a Dutch astronomer and a German.  But the comet has been known ever since as Cheseaux's comet, because de Cheseaux observed it closely for the next three months, and when the comet passed near the sun (passed through perihelion) on Mar. 1, 1744 and soon thereafter sprouted six tails, he was there to sketch the unprecedented phenomenon.  Better yet, within months, he brought to press a sizeable book on comets in general, and on the comet of 1743/44 in particular.  The book includes an engraving of the six-tailed comet, as drawn on Mar. 8/9, 1744, as well as several diagrams of the path of the comet through the heavens, and its orbit through the solar system, both before and after it grew the six tails.

The six-tailed comet of 1744, detail of an engraving in Jean-Philippe Loys de Cheseaux, Traité de la comete, 1744 (Linda Hall Library)




1883 Felix Klein notes in his references, "Received call to go to Baltimore. Great desire to go there -- at the least a new start." He had received an offer to replace J. J. Sylvester as the Professor of Mathematics at Johns Hopkins University in the form of a telegram from Danial Colt Gilman, President of the University. Klein's response contains two demands. The first is that he will not take less than the salary of the departing Sylvester, ($1000 a year more than the initial offer) and the second that his need for the economic security of his family should be somehow met (in Germany tenured positions included a pension that passed to the wife after the professor's death). Neither demand was met, and eventually Klein would go to Gottingen to develop his famous math institute. *Constance Reid, The Road Not Taken, Mathematical Intelligencer, 1978




1907 Emmy Noether received her Ph.D. degree, summa cum laude, from the University of Erlangen, for a dissertation on algebraic invariants directed by Paul Gordan. She went on to become the world’s greatest woman mathematician. [DSB 10, 137 and A. Dick, p. xiii] *VFR

Emmy's home in Erlangen




In 1920, first U.S. measurement of the size of a fixed star was made on Betelgeuse, the bright red star in the right shoulder of Orion, which was found to be 260 million miles in diameter - 150 times greater than the Sun. Dr. Francis G. Pease made the measurement on the 100-inch telescope at the Mount Wilson Observatory using a beam interferometer designed by Professor A. A. Michelson. Betelgeuse was selected as the first test object since theoretical calculations had suggested that the star was unusually great in size. The apparent angular size of Betelgeuse was found to average about .044 arcseconds. Direct interferometer measurements can only be used with large stars. The majority of stars rely upon more indirect methods of determining stellar sizes. *TIS

Size comparison between Arcturus, Rigel, S Doradus, Antares, and Betelgeuse



An illustration of Orion (horizontally reversed) in al-Sufi's Book of Fixed Stars. Betelgeuze is annotated as Yad al-Jauzā ("Hand of Orion"), one of the proposed etymological origins of its modern name, and also as Mankib al Jauzā' ("Shoulder of Orion").*Wik





1943 Croatia issued a pair of stamps to honor the Serbo-Croation mathematician and physicist Fr. Rugjer Boscovich (1711–1787). [Scott #59-60].*VFR







1957 Niels Bohr comes to Univ of Oklahoma for lecture on "Atoms and Human Knowledge." Jens Rud Nielsen, who joined the OU Physics Department in 1924, was an undergraduate student of Bohr in Denmark. Bohr, one of the founders of quantum mechanics, made two trips to the University of Oklahoma, first in 1937 and again in 1957. *U of Ok digital collection






1991 Stanford Linear Accelerator Center launches first Web site outside Europe
On December 13, 1991 the Stanford Linear Accelerator Center (SLAC) put up the first Web site outside Europe. It let physicists browse the full text of pre-publication scientific papers on SLAC's SPIRES database directly over the Web. This was a radical improvement over the old system, which involved submitting requests and waiting for fax or email versions to be sent back. As a vital service for the international physics community, the SLAC site became an important early step in helping the World Wide Web live up to its ambitious name *CHM




2024. The annual Geminids meteor shower, which streaks across the night sky every year in mid-December, will peak on Monday night and into Tuesday..  The best time to watch is after midnight through dawn on December 14. 

The meteors will appear to radiate from a point near the star Castor, in the constellation Gemini.

 Under a dark sky with no moon, you might catch 120 Geminid meteors per hour.



BIRTHS


1724 Franz Maria Ulrich Theodor Hoch Aepinus (13 Dec 1724; 10 Aug 1802.)
Dutch physicist whose Tentamen theoriae electricitatis et magnetismi (1759; "An Attempt at a Theory of Electricity and Magnetism") was the first work to apply mathematics to the theory of electricity and magnetism. Aepinus' experiments led to the design of the parallel-plate capacitor, a device used to store energy in an electric field. He also discovered the electric properties of the mineral tourmaline and investigated pyroelectricity, the state of electrical polarization produced in tourmaline and various other crystals by a change of temperature. Other achievements of Aepinus include improvements to the microscope, and his demonstration of the effects of parallax in the transit of a planet across the Sun's disk (1764). *TIS




1753 William Nicholson (13 December 1753 – 21 May 1815) was a renowned English chemist and writer on "natural philosophy" and chemistry, as well as a translator, journalist, publisher, scientist, inventor, patent agent and civil engineer.

 He is best known for discovering the electrolysis of water, a fundamental process in chemistry. He also published the first monthly scientific journal in Britain, the Journal of Natural Philosophy, Chemistry, and the Arts, which he edited from 1797 to 1814. 

In 1797 he began to publish and contribute to the Journal of Natural Philosophy, Chemistry and the Arts, generally known as Nicholson's Journal, the earliest monthly scientific work of its kind in Great Britain— the publication continued until 1814. The journal included the first comprehensive descriptions of aerodynamics with George Cayley's "On Aerial Navigation", which inspired the Wright brothers a hundred years later. In May 1800 he with Anthony Carlisle discovered electrolysis, the decomposition of water into hydrogen and oxygen by voltaic current. The two were then appointed to a chemical investigation committee of the new Royal Institution. But his own interests shortly turned elsewhere.
Besides considerable contributions to the Philosophical Transactions, Nicholson wrote translations of Fourcroy's Chemistry (1787) and Chaptal's Chemistry (1788), First Principles of Chemistry (1788) and a Chemical Dictionary (1795); he also edited the British Encyclopaedia, or Dictionary of Arts and Sciences (6 vols., London, 1809).
Nicholson died in Bloomsbury at the age of 61 on 21 May 1815. *Wik






1759 John Hailstone (13 Dec, 1759– 9 June, 1847), English geologist, born near London, was placed at an early age under the care of a maternal uncle at York, and was sent to Beverley school in the East Riding. Samuel Hailstone was a younger brother. John went to Cambridge, entering first at Catharine Hall, and afterwards at Trinity College, and was second wrangler and second in the Smith Prize of his year (1782). He was second in both competitions to James Wood who became master of Saint Johns, and Dean of Ely. Hailstone was elected fellow of Trinity in 1784, and four years later became Woodwardian Professor of Geology, an office which he held for thirty years.
He went to Germany, and studied geology under Werner at Freiburg for about twelve months. On his return to Cambridge he devoted himself to the study and collection of geological specimens, but did not deliver any lectures. He published, however, in 1792, ‘A Plan of a course of lectures.’
He married, and retired to the vicarage of Trumpington, near Cambridge, in 1818, and worked zealously for the education of the poor of his parish. He devoted much attention to chemistry and mineralogy, as well as to his favourite science, and kept for many years a meteorological diary. He made additions to the Woodwardian Museum, and left manuscript journals of his travels at home and abroad, and much correspondence on geological subjects. He was elected to the Linnean Society in 1800, and to the Royal Society in 1801, and was one of the original members of the Geological Society. Hailstone contributed papers to the ‘Transactions of the Geological Society’ (1816, iii. 243–50), the ‘Transactions of the Cambridge Philosophical Society’ (1822, i. 453–8), and the British Association (Report, 1834, p. 569). He died at Trumpington in his eighty-eighth year. *Wik




1805 Johann von Lamont (13 Dec 1805; 6 Aug 1879) Scottish-born German astronomer noted for discovering (1852) that the magnetic field of the Earth fluctuates with a 10.3-year activity cycle, but does not correlate it with the period of the sunspot cycle. From 1 Aug 1840, Johann von Lamont (as director of the Royal Astronomical Observatory in Munich) started regular and permanent observations of the earth's magnetic field. In the 1850's he started making regional magnetic surveys in the kingdom of Bavaria, later extended to other states in south Germany, France, Holland, Belgium, Spain, Portugal, Prussia and Denmark. His central European maps with isolines of geomagnetic elements, reduced to 1854, were the first worldwide. *TIS




1867 Kristian Olaf Bernhard Birkeland (born 13 December 1867 in Christiania (today's Oslo) – 15 June 1917 in Tokyo, Japan) was a Norwegian scientist, professor of physics at the Royal Fredriks University in Oslo. He is best remembered for his theories of atmospheric electric currents that elucidated the nature of the aurora borealis. In order to fund his research on the aurorae, he invented the electromagnetic cannon and the Birkeland–Eyde process of fixing nitrogen from the air. Birkeland was nominated for the Nobel Prize seven times.

Birkeland organized several expeditions to Norway's high-latitude regions where he established a network of observatories under the auroral regions to collect magnetic field data. The results of the Norwegian Polar Expedition conducted from 1899 to 1900 contained the first determination of the global pattern of electric currents in the polar region from ground magnetic field measurements.

Birkeland proposed in 1908 in his book The Norwegian Aurora Polaris Expedition 1902–1903 that polar electric currents, today referred to as auroral electrojets, were connected to a system of currents that flowed along geomagnetic field lines into and away from the polar region. Such field-aligned currents are known today as Birkeland currents in his honour. He provided a diagram of field-aligned currents in the book. The book on the 1902–1903 expedition contains chapters on magnetic storms on the Earth and their relationship to the Sun, the origin of the Sun itself, Halley's comet, and the rings of Saturn.

Birkeland's vision of what are now known as Birkeland currents became the source of a controversy that continued for over half a century, because their existence could not be confirmed from ground-based measurements alone. His theory was disputed and ridiculed at the time as a fringe theory by mainstream scientists, most notoriously by the eminent British geophysicist and mathematician Sydney Chapman who argued the mainstream view that currents could not cross the vacuum of space and therefore the currents had to be generated by the Earth. Birkeland's theory of the aurora continued to be dismissed by mainstream astrophysicists after his death in 1917.


Proof of Birkeland's theory of the aurora only came in 1967 after a probe was sent into space. The crucial results were obtained from U.S. Navy satellite 1963-38C, launched in 1963 and carrying a magnetometer above the ionosphere. Magnetic disturbances were observed on nearly every pass over the high-latitude regions of the Earth. These were originally interpreted as hydromagnetic waves, but on later analysis it was realized that they were due to field-aligned or Birkeland currents.

Norwegian 200-kroner banknote,





1887 George Pólya (13 Dec 1887 in Budapest, Hungary - 7 Sept 1985 in Palo Alto, California, USA) Pólya was arguably the most influential mathematician of the 20th century. His basic research contributions span complex analysis, mathematical physics, probability theory, geometry, and combinatorics. He was a teacher par excellence who maintained a strong interest in pedagogical matters throughout his long career. Before going to the United States Pólya had a draft of a book How to solve it written in German. He had to try four publishers before finding one to publish the English version in the United States but it sold over one million copies over the years and has been translated in 17 languages. Schoenfeld described its importance, "For mathematics education and the world of problem solving it marked a line of demarcation between two eras, problem solving before and after Pólya."

Pólya explained in How to solve it that to solve problems required the study of heuristic"The aim of heuristic is to study the methods and rules of discovery and invention .... Heuristic, as an adjective, means 'serving to discover'. ... its purpose is to discover the solution of the present problem. ... What is good education? Systematically giving opportunity to the student to discover things by himself."
He also gave the wise advice, "If you can't solve a problem, then there is an easier problem you can't solve: find it."
Pólya published further books on the art of solving mathematical problems. For example Mathematics and plausible reasoning (1954), and Mathematical discovery which was published in two volumes (1962, 1965).*SAU (The student or teacher who has not read any of these books should go immediately and read them.)

(Every student who dreams of doing advanced math should read "How to Solve it."  Every teacher at any level of mathematics should read it multiple times.)






1908 Leon Bankoff (December 13, 1908, New York City, NY -February 16, 1997, Los Angeles, CA), was an American dentist and mathematician.

After a visit to the City College of New York, Bankoff studied dentistry at New York University. Later, he moved to Los Angeles, California, where he taught at the University of Southern California; while there, he completed his studies. He practiced over 60 years as a dentist in Beverly Hills. Many of his patients were celebrities.
Along with Bankoff's interest in dentistry were the piano and the guitar. He was fluent in Esperanto, created artistic sculptures, and was interested in the progressive development of computer technology. Above all, he was a specialist in the mathematical world and highly respected as an expert in the field of flat geometry. Since the 1940s, he lectured and published many articles as a co-author. Bankoff collaborated with Paul Erdős in a mathematics paper and therefore has an Erdős number 1.
From 1968 to 1981, Bankoff was the editor of the Problem Department of Pi Mu Epsilon Journals, where he was responsible for the publication of some 300 top problems in the area of plane geometry, particularly Morley's trisector theorem, and the arbelos of Archimedes. Among his discoveries with the arbelos was the Bankoff circle, which is equal in area to Archimedes' twin circles. Martin Gardner called Bankoff, “one of the most remarkable mathematicians I have been privileged to know.” *Wik

The Bankoff Circle




1910 Charles Alfred Coulson FRS (13 December 1910, Dudley, England – 7 January 1974, Oxford, England) was a British applied mathematician, theoretical chemist and religious author.
His major scientific work was as a pioneer of the application of the quantum theory of valency to problems of molecular structure, dynamics and reactivity. He shared his deep religious belief, as a Methodist lay preacher, with the general public in radio broadcasts, served on the World Council of Churches from 1962 to 1968 and was Chairman of Oxfam from 1965 to 1971.
Coulson was a Senior Lecturer in the Mathematics Department of University College, Dundee, which was administratively part of the University of St. Andrews from 1938 to 1945. He held a Fellowship at the University of Oxford from 1945 to 1947, when he took up the newly appointed Chair of Theoretical Physics at King's College London. He returned to Oxford in 1952 as Rouse Ball Professor of Mathematics and Fellow of Wadham College. He set up and directed the Mathematical Institute. In 1972 he was appointed to the newly created Chair of Theoretical Chemistry, which has since been named for him.
He was elected a Fellow of the Royal Society of Edinburgh in 1941 and a Fellow of the Royal Society of London in 1950. He was awarded the Davy Medal of the Royal Society in 1970, the Faraday and Tilden Medals of the Chemical Society in 1968 and 1969 respectively, and received a dozen honorary degrees from English and other universities. He was a member of the International Academy of Quantum Molecular Science.
In each of his successive appointments, Coulson attracted an active and enthusiastic group of graduate students, short and long term visitors, many of whom held senior university and industrial positions in England and other countries. Many of his students went on to make major contributions in several fields of endeavour.
Coulson was an excellent cricketer and chess player, a warm family man and had a strong sense of humour. He and Eileen were gracious hosts to his students and his associates. The conference in his honour at Brasenose College in 1967 had an impressive international attendance, despite the difficulty of organizing it during a postal strike. *Wik




1921 David Gale (December 13, 1921 – March 7, 2008) was a distinguished American mathematician and economist. He was a Professor Emeritus at University of California, Berkeley, affiliated with departments of Mathematics, Economics, and Industrial Engineering​ and Operations Research. He has contributed to the fields of mathematical economics, game theory, and convex analysis.*Wik




1923 Philip Warren Anderson (13 Dec 1923, ) is an American physicist who (with John H. Van Vleck and Sir Nevill F. Mott) received the 1977 Nobel Prize for Physics for his research on semiconductors, superconductivity, and magnetism. He made contributions to the study of solid-state physics, and research on molecular interactions has been facilitated by his work on the spectroscopy of gases. He conceived a model (known as the Anderson model) to describe what happens when an impurity atom is present in a metal. He also investigated magnetism and superconductivity, and his work is of fundamental importance for modern solid-state electronics, making possible the development of inexpensive electronic switching and memory devices in computers. *TIS






DEATHS


1048 Abu Arrayhan Muhammad ibn Ahmad al-Biruni (15 Sept 973 in Kath, Khwarazm (now Kara-Kalpakskaya, Uzbekistan) - 13 Dec 1048 in Ghazna (now Ghazni, Afganistan)) one of the major figures of Islamic mathematics ((Al-Biruni was a Persian. His name (Birun) is a Persian word that means "abroad" and refers his birth place HT Mohammad Javidnia). He contributed to astronomy, mathematics, physics, medicine and history. the mathematical contributions of al-Biruni. These include: theoretical and practical arithmetic, summation of series, combinatorial analysis, the rule of three, irrational numbers, ratio theory, algebraic definitions, method of solving algebraic equations, geometry, Archimedes' theorems, trisection of the angle and other problems which cannot be solved with ruler and compass alone, conic sections, stereometry, stereographic projection, trigonometry, the sine theorem in the plane, and solving spherical triangles.

Important contributions to geodesy and geography were also made by al-Biruni. He introduced techniques to measure the earth and distances on it using triangulation. He found the radius of the earth to be 6339.6 km, a value not obtained in the West until the 16th century (see [50]). His Masudic canon contains a table giving the coordinates of six hundred places, almost all of which he had direct knowledge. Not all, however, were measured by al-Biruni himself, some being taken from a similar table given by al-Khwarizmi. The author of [27] remarks that al-Biruni seemed to realize that for places given by both al-Khwarizmi and Ptolemy, the value obtained by al-Khwarizmi is the more accurate.
Al-Biruni also wrote a treatise on time-keeping, wrote several treatises on the astrolabe and describes a mechanical calendar. He makes interesting observations on the velocity of light, stating that its velocity is immense compared with that of sound. He also describes the Milky Way as, "... a collection of countless fragments of the nature of nebulous stars. "
Topics in physics that were studied by al-Biruni included hydrostatics and made very accurate measurements of specific weights. He described the ratios between the densities of gold, mercury, lead, silver, bronze, copper, brass, iron, and tin. Al-Biruni displayed the results as combinations of integers and numbers of the form 1/n, n = 2, 3, 4, ... , 10. *SAU

An imaginary rendition of Al Biruni on a 1973 Soviet postage stamp




1557 Niccolò Fontana Tartaglia (1499, 13 Dec 1557) Italian mathematician who originated the science of ballistics. His proper name was Niccolo Fontana although he is always known by his nickname, Tartaglia, which means the "stammerer." When the French sacked Brescia in 1512, soldiers killed his father and left young Tartaglia for dead with a sabre wound that cut his jaw and palate. In 1535, by winning a competition to solve cubic equations, he gained fame as the discoverer of the formula for their algebraic solution (which was published in Cardan's Ars Magna, 1545) Tartaglia wrote Nova Scientia (1537) on the application of mathematics to artillery fire. He described new ballistic methods and instruments, including the first firing tables. He was the first Italian translator and publisher of Euclid's Elements (1543).*TIS





1565 Conrad Gessner (Konrad Gessner, Conrad Geßner, Conrad von Gesner, Conradus Gesnerus, Conrad Gesner; 26 March 1516 – 13 December 1565) was a Swiss naturalist and bibliographer. His five-volume Historiae animalium (1551–1558) is considered the beginning of modern zoology, and the flowering plant genus Gesneria (Gesneriaceae) is named after him. He is denoted by the author abbreviation Gesner when citing a botanical name. Gessner in 1551 was the first to describe adipose tissue; and in 1565 the first to document the pencil. *Wik See more at The Renaissance Mathematicus blog.



1603 Seigneur (lord) De La Bigotiere François Viète (1540, 13 Dec 1603) French mathematician who introduced the first systematic algebraic notation and contributed to the theory of equations. As Henry IV's cryptographer, he broke an elaborate cipher used by Spanish agents. In algebra, he made a number of innovations in the use of symbolism and several technical terms still in use (e.g., coefficient) were introduced by him. By using algebraic rather than geometric methods, Viète was able to solve a number of geometrical problems. In his In artem analyticam isagoge (1591) Viète introduced such basic algebraic conventions as using letters to represent both known and unknown quantities, while improving the notation for the expression of square and cubic numbers. *TIS













1870 William Chauvenet (24 May 1820, Milford, Pennsylvania - 13 December 1870, St. Paul, Minnesota) was an early American educator. A professor of mathematics, astronomy, navigation, and surveying, he was always known and well liked among students and faculty. In 1841 he was appointed a professor of mathematics in the United States Navy, and for a while served on Mississippi. A year later, he was appointed to the chair of mathematics at the naval asylum in Philadelphia, Pennsylvania. He was instrumental in the founding of the United States Naval Academy at Annapolis, Maryland. In 1859, he was offered a professorship at his alma mater at the same time he was offered a position at Washington University in St. Louis as professor of mathematics and astronomy. He chose St. Louis over New Haven and brought with him a deep love of music and a familiarity with the classics, in addition to being an outstanding figure in the world of science, noted by many historians as one of the foremost mathematical minds in the U.S. prior to the Civil War. It was Chauvenet who mathematically confirmed James B. Eads' plans for the first bridge to span the Mississippi River at St. Louis. The directors of the University chose him to be chancellor when his friend and Yale classmate Joseph Hoyt died in 1862. He came to his chancellorship in the midst of the Civil War in a state divided by the question of slavery.
Washington University went through a great period of growth during his chancellorship, adding dozens of professors, hundreds of students, and several new programs, including the establishment in 1867 of the law school. He served terms as vice president of the United States National Academy of Sciences and president of the American Association for the Advancement of Science, and was a member of both the American Philosophical Society and the American Academy of Arts and Sciences. After his death, the Mathematical Association of America established a prestigious prize in his honor, the Naval Academy named a mathematics building for him, and the U.S. Navy christened two ships Chauvenet.
*Wik



1921 Max Noether (24 Sept 1844 in Mannheim, Baden, Germany - 13 Dec 1921 in Erlangen, Germany) was one of the leaders of nineteenth century algebraic geometry. Although himself a very distinguished mathematician, his daughter Emmy Noether was to bring greater innovation to mathematics than did her father.*SAU

Brill and Max Noether developed alternative proofs using algebraic methods for much of Riemann's work on Riemann surfaces. Brill–Noether theory went further by estimating the dimension of the space of maps of given degree d from an algebraic curve to projective space Pn. In birational geometry, Noether introduced the fundamental technique of blowing up in order to prove resolution of singularities for plane curves.


Noether made major contributions to the theory of algebraic surfaces. Noether's formula is the first case of the Riemann-Roch theorem for surfaces. The Noether inequality is one of the main restrictions on the possible discrete invariants of a surface. The Noether-Lefschetz theorem (proved by Lefschetz) says that the Picard group of a very general surface of degree at least 4 in P3 is generated by the restriction of the line bundle O(1).

Noether and Castelnuovo showed that the Cremona group of birational automorphisms of the complex projective plane is generated by the "quadratic transformation" [x,y,z] ↦ [1/x, 1/y, 1/z]

together with the group PGL(3,C) of automorphisms of P2. Even today, no explicit generators are known for the group of birational automorphisms of P3.





1950 Abraham Wald (October 31, 1902 – December 13, 1950) was a mathematician born in Cluj, in the then Austria–Hungary (present-day Romania) who contributed to decision theory, geometry, and econometrics, and founded the field of statistical sequential analysis. He spent his researching years at Columbia University.Wald applied his statistical skills in World War II​ to the problem of bomber losses to enemy fire. A study had been made of the damage to returning aircraft and it had been proposed that armor be added to those areas that showed the most damage. Wald's unique insight was that the holes from flak and bullets on the bombers that returned represented the areas where they were able to take damage. The data showed that there were similar patches on each returning B-29 where there was no damage from enemy fire, leading Wald to conclude that these patches were weak spots and that they must be reinforced. *Wik

"Although Wald excelled academically, getting a bachelor’s degree and a PhD in mathematics, he couldn’t find employment in academia due to antisemitic discrimination. Fortunately, two prominent economists, first Karl Schlesinger and then Oskar Morgenstern, put his skills to work in the private sector.

When the Nazis annexed Austria in 1938, however, the situation for Jews got even more precarious, and Wald, like many others, sought to flee. He was able to get a job at the Cowles Commission for Research in Economics Yale University. Had he remained much longer in Austria, he very likely would have died in a concentration camp."  *Wendy Appleby


survivorship bias, notice the cockpit area



2004 David Wheeler, Inventor of the Closed Subroutine, Dies. Wheeler, born February 9, 1927, was Emeritus Professor of Computer Science at Cambridge University and a computer science pioneer. He worked on the original Cambridge EDSAC computer and wrote the first computer program to be stored in a computer’s memory. He pioneered the use of subroutines and data compression. He earned his Ph.D. in 1951 from Cambridge’s Computer Laboratory. (reputed to be the first Ph.D. in computer science) He spent time at the University of Illinois where he made contributions to the architecture of the ILLIAC system there. He later returned to the Cambridge Computer Laboratory and invented the Cambridge Ring and advanced methods of computer testing. He continued to work there until his death, a decade after he had officially retired. *CHM





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