Friday, 24 July 2026

On This Day in Math - July 24




In mathematics the art of proposing a question 
must be held of higher value than solving it.

~Goerg Cantor


Today is the 205th day of the year; there are 205 pairs of twin primes less than ten thousand. *Number Gossip

Every number greater than 205 is the sum of distinct primes of the form 6n + 1. *Prime Curios

205 is the number of walks of length 5 between any two distinct vertices of the complete graph K_5

205 is the smallest un-primeable odd composite  .  It can not be turned into a prime by changing only one of its digits.  (nice exploration for young students)  

205 = 14^2 + 3^2 = 13^2+6^2

205 = 103^2 - 102^2 = 23^2 - 18^2 The first is from a property of every odd number, the second is from a property of any number greater than 35 that ends in five.

205 = 2 x 41 + 41 + 41 x 2 also 54 + 45 + 7 + 54 + 45. or 99 + 7 + 99

205 is a palindrome in duodecimal (base 12, (151) =1 x 12^2 + 5 x 12 + 1), and in bases 9, 11, 13, and 16.


205 is the smallest un-primeable odd composite  .  It can not be turned into a prime by changing only one of its digits.  (Language fact: A prime which cannot be turned into another prime by changing a single digit is called weakly prime. These are all pretty big, the smallest being 294001.)

205 is a semi-prime, 5 x 41.  It is also a reversible semi-prime, or emirpimes, since it's reversal, 502 = 2 x 251, is also a semi-prime

Here for More Math Facts for every Math Date



EVENTS

In 1673, Edmund Halley entered Queen's College, Oxford, as an undergraduate. Halley had attended the prestigious St. Paul's school, where in 1671, he was appointed captain, a position resembling today's student body president. He was an excellent student, and by the time he entered Queen's College, Oxford. At this young age, Halley already possessed, "... the basic facts and computations not only of navigation but also those which the practical astronomer is concerned when he sets about the delicate task of measuring the positions of celestial bodies in the sky," according to Colin Ronan in his book Edmond Halley: genius in eclipse *TIS

*Wik




1860 Yale University authorized the granting of Doctor of Philosophy degrees. The first such degrees in the U.S. were awarded in 1861 by Yale to Eugene Schuyler, James Morris Whiton, and Arthur Williams Wright. [Kane, p. 215] *VFR  

Arthur Williams Wright (September 8, 1836 – December 19, 1915) was an American physicist. Wright spent most of his scientific career at Yale University, where he received the first science Ph.D. awarded outside of Europe. His research, which ranged from electricity to astronomy, produced the first X-ray image and experimented with Röntgen rays. He also proved instrumental in securing funding for the first dedicated physics laboratory building in the United States, the Sloane Physical Laboratory.

Eugene Schuyler (February 26, 1840 – July 16, 1890) was a nineteenth-century American scholar, writer, explorer and diplomat. Schuyler was one of the first three Americans to earn a Ph.D. from an American university; and the first American translator of Ivan Turgenev and Lev Tolstoi. He was the first American diplomat to visit Russian Central Asia, and as American Consul General in Istanbul he played a key role in publicizing Turkish atrocities in Bulgaria in 1876 during the April Uprising. He was the first American Minister to Romania and Serbia, and U.S. Minister to Greece.

Whitton, it seems was a language man who wrote several books about languages including , "

  • HandboHandbook of Exercises and Reading Lessons for Beginners in Latin

  •  (Boston: James Munroe and Company, 1860); First Lessons in Greek: 

  • The Beginner’s Companion-Book to Hadley’s Greek Grammar 

  • (New York: D. Appleton & Co., 1862, 1863, 1866, 1872, 1881);  

  • *Wik

  • Arthur William Wright  




1911, American Hiram Bingham discovered the Lost City of the Incas, Vilcapampa (now called Machu Picchu), where the last Incan Emperors found refuge from the conquistadors.*TIS


1950, the first successful rocket launch from Cape Canaveral took place. "Bumper" No. 8 was a captured German V-2 rocket with the payload replaced by another rocket 700-pound Army-JPL Wac Corporal rocket on top. It was fired from Long-Range Proving Ground at Cape Canaveral. The first-stage V-2 climbed 10 miles, separated from the second-stage Corporal which traveled 15 more miles. (V-2 exploded). A previous attempt on 19 July 1950 of a similar launch was aborted on the pad. 



1951  John Bardeen notified AT&T Bell Laboratories that he would be leaving the company where, along with Walter Brattain and William Shockley, he had developed one of the most essential components of modern computing: the point-contact transistor.

The transistor replaced vacuum tubes, allowing the size of computers to decrease dramatically while their power increased. Despite this triumph, Bardeen was unhappy with Shockley, whom he felt was limiting his and Brattain's involvement with further refinements to the transistor. Bardeen took a position at the University of Illinois at Urbana-Champaign. *CHM

*CHM



1991, A University of Manchester scientist announced the finding a planet outside of solar system. Andrew G. Lyne of the University of Manchester subsequently retracted his claim for a planet around pulsar PSR 1829-10 at the Jan 1992 meeting of the American Astronomical Society in Atlanta. He said that the modulation of radio waves coming from the pulsar was caused not by the presence of a planet but was in fact an artifact of the Earth's motion around the Sun. That possibility that had been considered but then discounted in earlier studies of the data.*TIS



BIRTHS

1786 Joseph Nicolas Nicollet (July 24, 1786 – September 11, 1843), also known as Jean-Nicolas Nicollet, was a French geographer, astronomer, and mathematician known for mapping the Upper Mississippi River basin during the 1830s. Nicollet led three expeditions in the region between the Mississippi and Missouri Rivers, primarily in Minnesota, South Dakota, and North Dakota.

Before emigrating to the United States, Nicollet was a professor of mathematics at Collège Louis-le-Grand, and a professor and astronomer at the Paris Observatory with Pierre-Simon Laplace. Political and academic changes in France led Nicollet to travel to the United States to do work that would bolster his reputation among academics in Europe. He was elected a member of the American Philosophical Society in 1842.

Nicollet's maps were among the most accurate of the time, correcting errors made by Zebulon Pike, and they provided the basis for all subsequent maps of the American interior. They were also among the first to depict elevation by hachuring (short parallel lines used in hill-shading on maps, their closeness indicating steepness of gradient) and the only maps to use regional Native American placenames. Nicollet's Map of the Hydrographical Basin of the Upper Mississippi was published in 1843, following his death. Nicollet Tower, located in Sisseton, South Dakota is a monument to Nicollet and his work and was constructed in 1991.



1827 Edward Olney (ALL-nee*) (July 24, 1827 - January 16, 1887) was born in Moreau, Saratoga County, New York. His ancestry can be traced back to Thomas Olney who accompanied Roger Williams in founding the city of Providence and colony of Rhode Island. Benjamin Olney's family moved to Oakland County, Michigan, in 1833 and, a few months later, settled on a farm in Weston, Wood County, Ohio.
Opportunities for formal education on the frontier were sparse, and Olney was largely self-taught. Calloway tells about Edward hiring a neighbor boy to drive the team of oxen on the Olney farm so that he could attend school for six weeks in order to master Day's Algebra. During this time he also ran an arithmetic school at home in the evenings in order to earn the money to pay for his substitute driver.
At age 19, Olney began his career as a teacher in the local elementary schools, while studying mathematics, natural science, and languages on his own. Cajori reports that "though he had never studied Latin, he began teaching it and kept ahead of the class because he 'had more application'." In 1848 Olney was hired as a teacher in the district school at Perrysburg, Ohio. The following year he was named principal of the grammar department in the new Union School. Over the next five years he would become the school's superintendent, marry Miss Sarah Huntington (a teacher at the school), and receive an honorary A. M. degree from Madison University (now Colgate University) in Hamilton, New York. Today there is an Olney School in Lake Township, Wood County, named after him.
In 1853 Olney was appointed Professor of Mathematics at Kalamazoo College, Michigan, where he remained for ten years and established the first mathematics curriculum at that institution. He inspired his colleagues and students alike with "his high Christian aims; his generous, self-sacrificing spirit; his thoroughness in government and discipline; and the inspiration which attended him." Although he insisted that his students recite using exact and correct language, he always tried to simplify the explanations of concepts and processes and make them more understandable. Kalamazoo college later conferred the honorary degree, LL. D. upon him.
In 1863 Olney was named Professor of Mathematics at the University of Michigan, succeeding George P. Williams, whose title was then changed to Professor of Physics. In those days the freshmen at Michigan were taught by inexperienced instructors, but once a week they had to recite for Professor Olney. His reputation for being a stern disciplinarian and a stickler for correct details earned him the nickname "Old Toughy." Nevertheless, he took great pains to see that the poorer students obtained help in making up their deficiencies. According to a former student, G. C. Comstock, "He was not a harsh man, and although the students stood in awe of him, I think that he was generally liked by them."
While he was at Michigan, Professor Olney began writing a series of successful mathematics textbooks for use in both grammar schools and colleges. In many places these displaced the works of such highly regarded authors as Charles Davies and Elias Loomis. Among the titles are: Elements of Arithmetic for Intermediate, Grammar, and Common Schools (1877), A University Algebra (1873), Elementary Geometry (1883), Elements of Trigonometry (1870), and A General Geometry and Calculus (1871) (online). Olney's treatment of calculus was criticized for using infinitesimal methods, but praised for giving "the elegant method, discovered by Prof. James C. Watson [Professor of Astronomy at Michigan], of demonstrating the rule for differentiating a logarithm without the use of series." It is said that Olney preferred geometry to analysis, and when teaching calculus, he would attempt to translate analytical expressions into their geometrical equivalents. This, along with his own struggles in self-education, contributed to his great success as a teacher and textbook author. Edward Olney died on January 16, 1887, after suffering for three years from the effects of a stroke. *David E. Kullman






1851 Friedrich Hermann Schottky. (24 July 1851 – 12 August 1935) was a German mathematician who worked on elliptic, abelian, and theta functions and invented Schottky groups. He was born in Breslau, Germany (now Wrocław, Poland) and died in Berlin.
He is also the father of Walter H. Schottky, the German physicist and inventor of a variety of semiconductor concepts

Schottky's thesis on conformal mapping was well regarded by Weierstrass. Published in journal form in 1877, it introduced automorphic functions and Schottky groups, to be developed several years later by Henri Poincaré and Felix Klein.

Schottky's 1887 paper contributed to the theory of Poincaré series.[8]

In algebraic geometry, the problem of characterizing when the abelian varieties of an algebraic curve are Jacobian varieties is called the Schottky problem. Initially posed by Bernhard Riemann, Schottky obtained the first results, for the case of genus 4, and made subsequent progress with his student Heinrich Jung. The problem was formally solved in 1986 by Takahiro Shiota but remains an area of active research.

In complex analysis, Schottky's theorem shows the existence of a bound on the value a holomorphic function can take on the unit disk..*Wik





1853 Henri-Alexandre Deslandres (July 24, 1853 – January 15, 1948) French astrophysicist who invented a spectroheliograph (1894) to photograph the Sun in monochromatic light (about a year after George E. Hale in the U.S.) and made extensive studies of the solar chromosphere and solar activity. He worked at the Paris and Meudon Observatories. His investigation of molecular spectra produced empirical laws presaging those of quantum mechanics. He observed spectra of planets and stars and measured their radial velocities of, and he determined the rotation rates of Uranus, Jupiter and Saturn (shortly after James E. Keeler).*TIS




1856 Emile Picard (24 July 1856 – 11 December 1941) born. Picard's mathematical papers, textbooks, and many popular writings exhibit an extraordinary range of interests, as well as an impressive mastery of the mathematics of his time. Modern students of complex variables are probably familiar with two of his named theorems. His lesser theorem states that every nonconstant entire function takes every value in the complex plane, with perhaps one exception. His greater theorem states that an analytic function with an essential singularity takes every value infinitely often, with perhaps one exception, in any neighborhood of the singularity. He also made important contributions in the theory of differential equations, including work on Picard–Vessiot theory, Painlevé transcendents and his introduction of a kind of symmetry group for a linear differential equation, the Picard group. In connection with his work on function theory, he was one of the first mathematicians to use the emerging ideas of algebraic topology. In addition to his path-breaking theoretical work, Picard also made important contributions to applied mathematics, including the theories of telegraphy and elasticity. His collected papers run to four volumes.
Like his contemporary, Henri Poincaré, Picard was much concerned with the training of mathematics, physics, and engineering students. He wrote a classic textbook on analysis and one of the first textbooks on the theory of relativity. Picard's popular writings include biographies of many leading French mathematicians, including his father in law, Charles Hermite.*Wik

He has to be the perfect Stereotype of Every French Inspector in cinema.




1871 Paul Epstein (July 24, 1871 – August 11, 1939) was a German mathematician. He is known for his contributions to number theory, in particular the Epstein zeta function.
Epstein was raised in Frankfurt where his father was a professor. He received his PhD in 1895 from the University of Strasbourg. From 1895 to 1918 he was a Privatdozent at the University in Strasbourg, which at that time was part of the German Empire. At the end of World War I the city of Strasbourg reverted to France, and Epstein, being German, had to return to Frankfurt.
Epstein was appointed to a non-tenured post at the university and he lectured in Frankfurt from 1919. Later he was appointed professor at Frankfurt. However, after the Nazis came to power in Germany he lost his university position. Because of his age he was unable to find a new position abroad, and finally committed suicide by abusing barbital, fearing Gestapo torture. *Wik




1888 Dunham Jackson (July 24, 1888, Bridgewater, Massachusetts – November 6, 1946) was a mathematician who worked within approximation theory, notably with trigonometrical and orthogonal polynomials. He is known for Jackson's inequality. He was awarded the Chauvenet Prize in 1935. His book Fourier Series and Orthogonal Polynomials (dated 1941) was reprinted in 2004.
Harold Bacon recalls that Jackson was an inspired writer of limericks. When Bacon purchased Jackson's "The Theory of Approximations" he took it to Jackson's office and requested he sign it, suggesting a limerick. Without any visible prethought Jackson wrote on the flyleaf:

There was a young fellow named Bacon
Whose judgement of books was mistaken
In a moment too rash
He relinquished some cash
And his faith in the Author was shaken

*Steven Krantz, Mathematical Apocrypha Redux




1917 Clarence Francis Stephens (July 24, 1917 – March 5, 2018) was an American mathematician. He is credited with inspiring students and faculty at SUNY Potsdam to form the most successful United States undergraduate mathematics degree programs in the past century.[citation needed] Stephens was recognized by Mathematically Gifted & Black as a Black History Month 2018 Honoree.

The fifth of six children, he was orphaned at the age of eight. For his early education, he attended Harbison Agricultural and Industrial Institute, a boarding school for African-Americans in Irmo, South Carolina under Dean R. W. Bouleware and later President Rev John G. Porter.

Stephens graduated from Johnson C. Smith University in 1938 with a B.S. degree in mathematics. He received his M.S. (1939) and his Ph.D. (1944) from the University of Michigan, with a thesis on Non-Linear Difference Equations Analytic in a Parameter under James Nyswander.

After serving in the U.S. Navy (1942–1946) as a Teaching Specialist, Dr. Stephens joined the mathematics faculty of Prairie View A&M University. The next year (1947) he was invited to join the mathematics faculty at Morgan State University.

As a Mathematics Association of America (MAA) biography explains, “Dr. Stephens' focus was on being a research mathematician, so he accepted the position in part because he would be near a research library at Johns Hopkins University. While at Morgan State University, Dr. Stephens became appalled at what a poor job was being done in general to teach and inspire students to learn mathematics. He changed his focus from being a researcher to achieving excellence, with desirable results, in teaching mathematics.

In 1953, he received a one-year Ford Fellowship to study at the Institute for Advanced Study in Princeton, New Jersey.

Dr. Stephens remained at Morgan State until 1962, where is credited with initiating the program which led to five students achieving 91% to 99% on the graduate record exam in mathematics, three of these students (Earl R. Barnes, Arthur D. Grainger and Scott W. Williams) became the only three students of the same class at a Historically Black College to earn a PhD in mathematics. Stephens accepted an appointment as professor of mathematics at SUNY Geneseo. In 1969 he left Geneseo to join the mathematics faculty at SUNY Potsdam, where he served as chair of the mathematics department until his retirement in 1987.

The MAA biography reports that during Dr. Stephens’ tenure at SUNY Potsdam "the department became nationally known as a model of teaching excellence in mathematics. For several of these years the program was among the top producers of mathematics majors in the country. The teaching techniques that Professor Stephens introduced at Potsdam, and earlier at Morgan State, have been adopted by many mathematics departments across the country. They have been described in publications by the MAA, and recently in a book, Math Education At Its Best: The Potsdam Model, by Datta (Center for Teaching/Learning of Mathematics, 1993)." He turned 100 in July 2017 and died in March 2018. *Wik



1923 Christine Mary Hamill (July 24, 1923 – March 24, 1956) was an English mathematician who specialized in group theory and finite geometry. After receiving her Ph.D. at the University of Cambridge in 1951, she was appointed to a lectureship in the University of Sheffield and later was appointed lecturer in the University College, Ibadan, Nigeria.*Wik




DEATHS


1934 Hans Hahn (September 27, 1879 – July 24, 1934) was an Austrian mathematician who is best remembered for the Hahn-Banach theorem. He also made important contributions to the calculus of variations, developing ideas of Weierstrass. *SAU

1964 Finlay Freundlich (May 29, 1885 – July 24, 1964) was a distinguished German astronomer who worked with Einstein on measurements of the orbit of Mercury to confirm the general theory of relativity. He left Germany to avoid Nazi rule and became the Napier Professor of Astronomy at St Andrews. *SAU

1974 Sir James Chadwick (20 October 1891 – 24 July 1974) English physicist who received the Nobel Prize for Physics (1935) for his discovery of the neutron. He studied at Cambridge, and in Berlin under Geiger, then worked at the Cavendish Laboratory with Rutherford, where he investigated the structure of the atom. He worked on the scattering of alpha particles and on nuclear disintegration. By bombarding beryllium with alpha particles, Chadwick discovered the neutron - a neutral particle in the atom's nucleus - for which he received the Nobel Prize for Physics in 1935. In 1932, Chadwick coined the name "neutron," which he described in an article in the journal Nature. He led the UK's work on the atomic bomb in WW II, and was knighted in 1945*TIS



1983 Eberhard Frederich Ferdinand Hopf (April 4, 1902, Salzburg, Austria-Hungary – July 24, 1983, Bloomington, Indiana) was a mathematician and astronomer, one of the founding fathers of ergodic theory and a pioneer of bifurcation theory who also made significant contributions to the subjects of partial differential equations and integral equations, fluid dynamics, and differential geometry. The Hopf maximum principle is an early result of his (1927) which is one of the most important techniques in the theory of elliptic partial differential equations.*Wik
"The modern theory of relativity of Mr Einstein predicts an influence of any field of gravitation upon light passing near to the sun. The gravitation would have, according to the investigation of Einstein, the effect of deflecting the ray of the star, and Mr Einstein asked me if I would try to prove his results by observations." *SAU 




1992 Lillian Rose Vorhaus Kruskal Oppenheimer (October 24, 1898 in New York City – July 24, 1992) was an American origami pioneer. She popularized origami in the West starting in the 1950s, and is credited with popularizing the Japanese term origami in English-speaking circles, which gradually supplanted the literal translation paper folding that had been used earlier. In the 1960s she co-wrote several popular books on origami with Shari Lewis.
She was the mother of three sons William Kruskal(developed the Kruskal-Wallis one-way analysis of variance), Martin David Kruskal(co-inventor of solitons and of surreal numbers), and Joseph Kruskal ( Kruskal's algorithm for computing the minimal spanning tree (MST) of a weighted graph) who all went on to be prominent mathematicians. Her grandson Clyde P. Kruskal (son of Martin) is an American computer scientist,working on parallel computing architectures, models, and algorithms. *Wik
*Origami Heaven



2005 Sir Richard Doll (28 October 1912 – 24 July 2005) British epidemiologist who was one of the first two researchers to link cigarette smoking to lung cancer, as published in the British Medical Journal in 1950. In the same journal, fifty years later, Doll published (22 Jun 2004) the first research that quantified the damage over the lifetime of a generation, based on a 50-year study of a group of almost 35,000 British doctors who smoked. The study found that almost half of persistent cigarette smokers were killed by their habit, and a quarter died before age 70. Persons who quit by age 30 had normal life expectancy. Even quitting at age 50 saved six more years of life over those who continued smoking. He studied other health effects, such as those caused by asbestos and electromagnetic fields.*TIS




2014 David S. Broomhead (13 November 1950 – 24 July 2014) was a British mathematician specializing in dynamical systems and was professor of applied mathematics at the School of Mathematics, University of Manchester.
After a year as a postdoc at the Atomic Energy Research Establishment, Broomhead moved to Japan. He held at two-year NATO Postdoctoral Fellowship in the Department of Physics at the University of Kyoto, in K. Tomita's group. On returning to the U.K., he worked as a postdoc with George Rowlands at the University of Warwick, again in the Physics Department. In 1983, Broomhead began working in the Signal Processing group at the Royal Signals and Radar Establishment (RSRE, now QinetiQ) in Malvern, becoming Senior Principal Scientific Officer. In 1995 he moved to Manchester, taking a Chair in Applied Mathematics, initially at UMIST and then after 2004, at the School of Mathematics at the new University of Manchester.
In Japan, Broomhead began to work seriously on applied nonlinear dynamics and chaos. With Greg King he developed techniques to determine whether an experimental time series had been generated by a deterministic chaotic system by combining the pure mathematical results on topological embedding due to Takens with the engineering method of singular value decompositions.
He died suddenly on 24 July 2014 at the National Hospital in London.







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

Thursday, 23 July 2026

On This Day in Math - July 23

 


Men love to wonder, and that is the seed of science.


-Ralph Waldo Emerson

The 204th Day of the Year
204 is the eighth tetrahedral number, the sum of the squares from 1 to 8. Answers the question, how many squares are there on an 8x8 checkerboard.

204 = 20^2 - 14^2=52^2 - 50^2

204 is the sum of consecutive primes in two different ways: as the sum of a twin prime (101 + 103) and as the sum of six consecutive primes (23 + 29 + 31 + 37 + 41 + 43). (one might wonder what is the smallest number that is the sum of consecutive primes in more than one way... And what is the smallest prime number that is expressible as the sum of consecutive Primes in more than one way?)

And a trio from *Derek Orr @MathYearRound :
204 = 1²+2²+3²+4²+5²+6²+7²+8².

Sum of first 204 primes is prime.


100...00099...999 (204 0's and 204 9's) is prime.

204 is a refactorable number, it is divisible by the count of its divisors, 12

It is because it is divisible by 12 that 204 is expressible as (n+3)^2 - (n-3)^2 for n= 17 (204/12=17)

204^2 = 41616, a number that is both a square and a triangular number, the 288th triangular number. They are pretty rare as it is only the fourth. And like 204, it is the sum of twin primes also, 41616 = 20807 + 20809. Only 12 and 84 also are the sum of twin primes with a square that is also the sum of twin primes.
since I've written twin primes so many times in this entry, its probably a good time to remind you that, although the idea of primes separated by only a single composite number was known back to antiquity, the term was created around the end of the 19th century by German Mathematician Paul Stackel (in the German, of course, "Primezahlzwilling")

On an infinite chess board, a Knight can reach 204 different squares in eight moves.

200 is CC in Roman numerals, and 204 is CC in hexadecimal.

For More Math Facts for Every Year Date





EVENTS


594 The Sun was well up (17°) at 6:11 am when totality occurred. On a warm summer's morning it must have got surprisingly cold as totality approached, giving a clue that something unusual was about to happen. At 258 km wide this was an Eclipse with a very wide track and a good duration of over 3 minutes. The Eclipse track traveled into Denmark, Norway, Sweden, Finland, Estonia and Russia. *NSEC


1754 Joseph Louis Lagrange, 18, published his first work in the form of a letter in Italian (He was Italian born. Only his great-great-grandfather Lagrange was French, all other ancestors were Italian). A month later he realized that he had rediscovered Leibniz’s formula for the n-th derivative of a product. *VFR




1788 Jefferson's interest in surveying, and measurement in general led him to inquire of Benjamin Vaughan, then of England, about a British odometer, "I have heard that they make in London an Odometer, which may be made fast between two spokes of any wheel, and will indicate the revolutions of the wheel by means of a pendulum which always keeps it’s vertical position while the wheel is turning round and round. Thus [see Fig. 1.] I will thank you to inform me whether it’s indications can be depended on, and how much the instrument costs. " *Jefferson Letters


1829, William Austin Burt, a surveyor, of Mount Vernon, Michigan, received a patent for his typographer, a forerunner of the typewriter (U.S. No. 5581X). The Patent Office fire of 1836 destroyed the original patent model. Burt's typographer was a heavy, box-like contraption, made almost entirely of wood. Like today's familiar toy typewriter, the typographer had type mounted on a metal wheel, with a rotating, semicircular frame. By turning a crank, Burt was able to move the wheel until it came to the letter he wanted. Then he would pull a lever, driving the type against the paper and making an inked impression. *TIS

 It was the first typewriting machine to be patented in the United States, although Pellegrino Turri had made one in Italy in 1808.Perhaps because of its slow speed, or because there was not yet a wide market for typewriters, it was not a commercial success

The working model that Burt constructed for his 1829 patent was destroyed in the 1836 Patent Office fire

*Wik


1904 The ice cream cone was introduced at the St. Louis world’s fair.*VFR by some accounts, the ice cream cone was invented by Charles E. Menches during the Louisiana Purchase Exposition in St. Louis. *TIS

To Whichever or both, Well done.  (That is an attempt at humor, the two names are both used for the same event.)

Although Menches is often named as the first to serve his ice cream in a rolled waffle cone, its true originator is far from clear. The edible cone was widely sold at the fair, and various other people there are also claimed as the innovator. *Tis



1923  On this day in 1923, Werner Werner Heisenberg went before his ptofessors to defend his PhD thesis, and dearly failed.


Heisenberg’s oral examiners included:

Arnold Sommerfeld (advisor, theoretical physics)
Wilhelm Wien (experimental physics, Nobel laureate)
Ferdinand von Lindemann (mathematics — famous for proving π is transcendental)

When Wien asked him basic experimental physics questions — for instance, about the workings of a simple lens or how a storage battery functions — Heisenberg failed to answer properly.
Heisenberg, brilliant at abstract theory but inexperienced in practical lab work, didn’t know basic lab instruments!  Reportedly, Wien was so shocked that he wanted to fail Heisenberg outright.
Arnold Sommerfeld, recognizing Heisenberg’s exceptional theoretical talent, intervened on his behalf.

Sommerfeld is said to have told the examiners:
“Gentlemen, Heisenberg is a theoretical physicist. If he understood experimental physics well, he would not be a theoretical physicist!”  Ultimately, Heisenberg passed — but barely:

His final grade was “ausreichend”, meaning “sufficient” or just a pass.

Despite his shaky defense, Heisenberg went on to revolutionize physics: In 1925, only two years later, he published his groundbreaking paper laying the foundations of quantum mechanics.

In 1932, he received the Nobel Prize in Physics for the creation of quantum mechanics. *PBnotes



1927 The English term Eigenvalue first appears in a letter to Nature from A. S. Eddington beginning “Among those ... trying to acquire a general acquaintance with Schrödinger's wave mechanics there must be many who find their mathematical equipment insufficient to follow his first great problem—to determine the eigenvalues and eigenfunctions for the hydrogen atom" *Jeff Miller, Earliest Known Uses of Some of the Words of Mathematics
The term was derived from Hilbert’s use of “Eigenwert” in 1904, although Helmholtz had earlier used “Eigentöne” for what he called proper tones in acoustics. proper was also used by many English and American scientists throughout the 1920-1950 period. Even J. Von Neumann’s translations into English used the term “proper“.
Paul Halmos followed von Neumann’s English writings and used “proper value” in his widely-used Finite Dimensional Vector Spaces (1958). However Halmos admitted defeat in his A Hilbert Space Problem Book (1967, p. x):

“For many years I have battled for proper values, and against the one and a half times translated German-English hybrid that is often used to refer to them. I have now become convinced that the war is over, and eigenvalues have won it; in this book I use them.”

 



1962 Tens of millions of people watched a historic broadcast as Telstar beamed live transatlantic video into viewers’ living rooms for the first time. The age of satellite television had dawned.
In homes across Rome, people barely touched their dinners. London’s pubs were packed, but bartenders served nary a drink. Throughout Europe, more than 100 million people huddled around television sets on the evening of July 23, 1962, to tune in to history. With Europeans watching eagerly, a black-and-white image of the Statue of Liberty flickered onto their screens. The picture itself was not particularly noteworthy except for one thing: it was live, via satellite. *History.Com
The first broadcast was to have been remarks by President John F. Kennedy, but the signal was acquired before the president was ready, so the lead-in time was filled with a short segment of a televised game between the Philadelphia Phillies and the Chicago Cubs at Wrigley Field before the President's address. A routine fly ball hit by Phillies second baseman Tony Taylor made telecommunications history.I have a different date and perspective from a BBC History page.  "On 11 July 1962 British television viewers saw pictures beamed live from the US via the Telstar satellite. Raymond Baxter and Richard Dimbleby were on hand to provide commentary, although the precise time of the broadcast was not known in advance. The first pictures, received in Britain just after 1am, were of the chairman of AT&T, Frederick Kappel, and of poor quality, while in France they were picked up clearly. However this landmark transmission marked the beginning of satellite broadcasting, and changed the face of telecommunications."

Telstar 1 was the first satellite capable of relaying television signals from Europe to North America. The 171-pound, 34.5-inch sphere loaded with transistors and covered with solar panels was placed in orbit by a Delta rocket launched from Cape Canaveral on July 10, 1962.

The maiden program included more images from around America, such as the Mormon Tabernacle Choir singing at Mount Rushmore and President John F. Kennedy conducting a press conference. 




1985 the legendary Commodore Amiga was released In 1985 Commodore revolutionized the home computer market by introducing the high end Commodore Amiga with a graphic power that was unheard of by that time in this market segment. Based on the Motorola 68000 microprocessor series the Amiga was most successful as a home computer, with a wide range of games and creative software, although early Commodore advertisements attempted to cast the computer as an all-purpose business machine. In addition, it was also a less expensive alternative to the Apple Macintosh and IBM-PC as a general-purpose business or home computer. The platform became particularly popular as a gaming platform. *blog.yovisto.com



1995
 The comet Hale–Bopp was discovered on July 23, 1995, independently by two observers, Alan Hale and Thomas Bopp, both in the United States. Hale–Bopp's orbital position was calculated as 7.2 astronomical units (AU) from the Sun, placing it between Jupiter and Saturn and by far the greatest distance from Earth at which a comet had been discovered by amateurs. It was discovered at such a great distance from the Sun that it raised expectations that the comet would brighten considerably by the time it passed close to Earth. Although predicting the brightness of comets with any degree of accuracy is very difficult, Hale–Bopp met or exceeded most predictions when it passed perihelion on April 1, 1997. The comet was dubbed the Great Comet of 1997.

The image is by my former student Dan Durda, of Sterling, Michigan; who may have acquired some math knowledge from me, but not his artistic sense.


2026  If the leaks are right, the Field's Medal will have it's third female winner.  

The list of 2026 Fields Medal winners has been inadvertently leaked, revealing that Peking University alumni Hong Wang and Yu Deng are among the recipients. This marks a historic moment as it is the first time two Chinese mathematicians will receive the prestigious award in the same edition. The leak occurred when four Fields Medal laureate lecture fields, marked "HIDDEN," were discovered in the front-end code of the ICM 2026 official schedule. A curl command generated by Codex revealed the names Yu Deng, John Pardon, Jacob Tsimerman, and Hong Wang. If confirmed on July 23, this will be a significant milestone for Chinese mathematics. Notably, Hong Wang will become the third female mathematician in history to receive the Fields Medal, further highlighting the groundbreaking nature of this achievement.


And it was so!!!

Hong Wang (Chinese: 王虹; pinyin: Wáng Hóng; born 1991) is a Chinese mathematician known for her research in Fourier analysis and geometric measure theory. She was awarded the Maryam Mirzakhani New Frontiers Prize in 2022, the Salem Prize in 2025, and the Fields Medal in 2026. *Wik


Jacob Tsimerman (born April 26, 1988) is a Canadian mathematician at the University of Toronto specialising in number theory and related areas. He was awarded the SASTRA Ramanujan Prize in the year 2015 in recognition for his work on the André–Oort conjecture and for his work in both analytic number theory and algebraic geometry. In 2026, he received the Fields Medal for his work on O-minimality, Griffiths' conjecture, and the Andre-Oort conjecture *Wik 



Yu Deng (Chinese: 邓煜; pinyin: Dèng Yù, born June 1989) is a Chinese mathematician and a professor of mathematics at the University of Chicago. He is known for his contributions to partial differential equations, fluid dynamics, and probabilistic analysis. He was awarded the Fields Medal in 2026.*Wik 



John Vincent Pardon (born June 1, 1989) is an American mathematician who works on geometry and topology. He is primarily known for having solved Gromov's problem on distortion of knots, for which he received the 2012 Morgan Prize. He is a permanent member of the Simons Center for Geometry and Physics in Stony Brook, New York. He was awarded the Fields Medal in 2026.*Wik




2026  Congratulations to Team USA! (And to all the competitors from every nation)

At the 67th International Mathematical Olympiad, held in Shanghai from July 10 to July 20, the six-student team organized by the MAA placed 2nd overall among 117 participating teams, the largest field in IMO history.

Team USA qualifies through the MAA American Mathematics Competitions, in which roughly 300,000 students from over 6,000 schools and learning centers participate each year. Top performers are invited to the MAA Mathematical Olympiad Summer Program for intensive training. *MAA






BIRTHS


1773 Sir Thomas Makdougall Brisbane, (23 July 1773 – 27 January 1860) Baronet British soldier and astronomical observer for whom the city of Brisbane, Australia, is named. He was Governor of NSW (1821-25). Mainly remembered as a patron of science, he built an astronomical observatory at Parramatta, Australia, made the first extensive observations of the southern stars since Lacaille in (1751-52) and built a combined observatory and magnetic station at Makerstoun, Roxburghshire, Scotland. He also conducted (largely unsuccessful) experiments in growing Virginian tobacco, Georgian cotton, Brazilian coffee and New Zealand flax.*TIS




1775 Etienne Louis Malus (23 July 1775 – 24 February 1812) born in Paris. He was the son on the Treasurer of France. His primary interest was mathematical optics. [Ivor Grattan-Guiness, Convolutions in French Mathematics, 1800–1840, p. 473] *VFR He studied geometric systems called ray systems, closely connected to Julius Plücker's line geometry. He conducted experiments to verify Christiaan Huygens' theories of light and rewrote the theory in analytical form. His discovery of the polarization of light by reflection was published in 1809 and his theory of double refraction of light in crystals, in 1810.
Malus attempted to identify the relationship between the polarising angle of reflection that he had discovered, and the refractive index of the reflecting material. While he deduced the correct relation for water, he was unable to do so for glasses due to the low quality of materials available to him (most glasses at that time showing a variation in refractive index between the surface and the interior of the glass). It was not until 1815 that Sir David Brewster was able to experiment with higher quality glasses and correctly formulate what is known as Brewster's law.
Malus is probably best remembered for Malus' law, giving the resultant intensity, when a polariser is placed in the path of an incident beam. His name is one of the 72 names inscribed on the Eiffel tower.*Wik




1854 Ivan Vladislavovich Sleszynski (23 July 1854 in Lysianka, Cherkasy, Kiev gubernia, Ukraine - 9 March 1931 in Kraków, Poland)Sleszynski's main work was on continued fractions, least squares and axiomatic proof theory based on mathematical logic. In a paper of 1892, based on his doctoral dissertation, he examined Cauchy's version of the Central Limit Theorem using characteristic function methods, and made several significant improvements and corrections. Because of the work, he is recognised as giving the first rigorous proof of a restricted form of the Central Limit Theorem. *SAU




1856 Bal Gangadhar Tilak  (23 July 1856 – 1 August 1920, age 64) Scholar, mathematician, philosopher, and militant nationalist who helped lay the foundation for India's independence. Tilak was a great Sanskrit scholar and astronomer. He fixed the origin and date of Rigvedic Aryans, which was highly acclaimed and universally accepted by orientalists of his time. He founded (1914) and served as president of the Indian Home Rule League and, in 1916, concluded the Lucknow Pact with Mohammed Ali Jinnah, which provided for Hindu-Muslim unity in the struggle for independence.*TIS



1886 Walter Schottky (23 July 1886, Zürich, Switzerland – 4 March 1976, Pretzfeld, West Germany) Swiss-born German physicist whose research in solid-state physics led to development of a number of electronic devices. He discovered the Schottky effect, an irregularity in the emission of thermions in a vacuum tube and invented the screen-grid tetrode tube (1915). The Schottky diode is a high speed diode with very little junction capacitance (also known as a "hot-carrier diode" or a "surface-barrier diode.") It uses a metal-semiconductor junction as a Schottky barrier, rather than the semiconductor-semiconductor junction of a conventional diode. *TIS




1906 Vladimir Prelog (23 July 1906 – 7 January 1998) Yugoslavian-born Swiss chemist who shared the 1975 Nobel Prize for Chemistry with John W. Cornforth for his work on the stereochemistry of organic molecules and reactions. Stereochemistry is the study of the three-dimensional arrangements of atoms within molecules. He authored systematic naming rules for molecules and their mirror-image version, that is, which configuration will be referred to as "dextra" and which will be the "levo" (right or left). Also, by X-ray diffraction, he elucidated the structure of several antibiotics.*TIS



1914 William Wager Cooper (July 23, 1914 – June 20, 2012) was an American operations researcher, known as a father of management science and as "Mr. Linear Programming". He was the founding president of The Institute of Management Sciences, founding editor-in-chief of Auditing: A Journal of Practice and Theory, a founding faculty member of the Graduate School of Industrial Administration at the Carnegie Institute of Technology (now the Tepper School of Business at Carnegie Mellon University), founding dean of the School of Urban and Public Affairs (now the Heinz College) at CMU, the former Arthur Lowes Dickinson Professor of Accounting at Harvard University, and the Foster Parker Professor Emeritus of Management, Finance and Accounting at the University of Texas at Austin.

 Cooper was born in Birmingham, Alabama and grew up in Chicago, where his father (a former bookkeeper) owned several gasoline stations that closed in the Great Depression. Cooper, in his second year of high school, dropped out to help support his family. He worked in a bowling alley, on a golf course, and as a professional boxer. As a boxer, he won 58 bouts, lost three, and drew two. While commuting to the golf course, he met Eric Kohler, a professor at Northwestern University, who pushed him to go back to school and bankrolled his entry to the University of Chicago. At Chicago, he began studying physical chemistry but was inspired by his work for Kohler on a legal case to switch to economics, graduating with a B.A. and Phi Beta Kappa honors in 1938.

After graduation, from 1938 to 1940, he worked as an accountant for the Tennessee Valley Authority, where Kohler had become Controller. There, he worked on performance auditing and the mathematical allocation of resources, and helped Kohler testify to a congressional investigative committee. In 1940, Cooper started doing graduate studies at Columbia University; however, in 1942, with his coursework completed but his thesis unwritten, he left Columbia to serve his country during World War II. He worked in the Division of Statistical Standards of the U.S. Bureau of the Budget coordinating the government programs that collected accounting statistics; his 1945 paper describing his wartime activities was the first recipient of an award from the American Institute of Accountants for the best paper of the year.

Cooper began his academic career with a brief teaching stint, from 1944 to 1946, back at the University of Chicago. In 1945, Cooper married his wife Ruth, a lawyer and human activist, and in 1946 he joined the newly formed Graduate School of Industrial Administration at the Carnegie Institute of Technology (now the Tepper School of Business at Carnegie Mellon University). There, he formed important research collaborations with Abraham Charnes, George Leland Bach, and Herbert A. Simon, and eventually became University Professor. While at CMU, from 1949 to 1950, he also worked again as an assistant to Eric Kohler, who had by this time become Comptroller of the Marshall Plan.In 1969 he left GSIA but stayed at CMU, becoming dean of the new School of Urban and Public Affairs (now the Heinz College) there. As dean, he realized that there would soon be a much greater role in American business management for African-Americans, and worked to increase African-American representation within the school.

In 1975, Harvard University hired Cooper away from CMU to become the Dickinson Professor of Accounting, and in 1980 he moved again, to the University of Texas at Austin, where he became the Foster Parker Professor of Management, Finance and Accounting. He retired in 1993, but continued to be active in research until his death on June 20, 2012.




1920 Herbert Federer (July 23, 1920 – April 21, 2010) was an American mathematician. He is one of the creators of geometric measure theory, at the meeting point of differential geometry and mathematical analysis.

Federer was born July 23, 1920, in Vienna, Austria. After emigrating to the US in 1938, he studied mathematics and physics at the University of California, Berkeley, earning the Ph.D. as a student of Anthony Morse in 1944. He then spent virtually his entire career as a member of the Brown University Mathematics Department, where he eventually retired with the title of Professor Emeritus.

Federer wrote more than thirty research papers in addition to his book Geometric measure theory. The Mathematics Genealogy Project assigns him nine Ph.D. students and well over a hundred subsequent descendants. His most productive students include the late Frederick J. Almgren, Jr. (1933–1997), a professor at Princeton for 35 years, and his last student, Robert Hardt, now at Rice University.

Federer was a member of the National Academy of Sciences. In 1987, he and his Brown colleague Wendell Fleming won the American Mathematical Society's Steele Prize "for their pioneering work in Normal and Integral currents."

In the 1940s and 1950s, Federer made many contributions at the technical interface of geometry and measure theory. Particular themes included surface area, rectifiability of sets, and the extent to which one could substitute rectifiability for smoothness in the classical analysis of surfaces. A particularly noteworthy early accomplishment (improving earlier work of Abram Besicovitch) was the characterization of purely unrectifiable sets as those which "vanish" under almost all projections. Federer also made noteworthy contributions to the study of Green's theorem in low regularity. The theory of capacity with modified exponents was developed by Federer and William Ziemer.[FZ73] In his first published paper, written with his Ph.D. advisor Anthony Morse, Federer proved the Federer–Morse theorem which states that any continuous surjection between compact metric spaces can be restricted to a Borel subset so as to become an injection, without changing the image.*Wik



1920 Chushiro Hayashi (July 23, 1920 – February 28, 2010) Japanese astrophysicist who with his coworkers created evolutionary models for stars of mass between 0.01 to 100 times that of the Sun. In 1950, he contributed to the abg (Alpher, Bethe, Gamow) (also see April 1, Events) model of nucleosynthesis in the hot big bang. Hayashi pioneered in modeling stellar formation and pre-main sequence evolution along “Hayashi tracks” (1961) downward on the Hertzprung-Russell diagram until stars reach the main sequence. He and Takenori Nakano studied the formation of low-mass, brown dwarf stars. Hayashi also investigated the formation of the solar system and of the earth and its atmosphere. He retired in 1984. He was presented the Bruce Medal in 2004 for lifetime contributions to astronomy.*TIS




1928 Vera Rubin (July 23, 1928 – December 25, 2016) was an American astronomer who pioneered work on galaxy rotation rates. She uncovered the discrepancy between the predicted and observed angular motion of galaxies by studying galactic rotation curves. By identifying the galaxy rotation problem, her work provided evidence for the existence of dark matter. These results were later confirmed over subsequent decades. *Wik

Throughout her schooling, Rubin faced the banal sexism all too common at the time for women interested in science. Her high school physics teacher ignored the few girls in class; a college admissions interviewer encouraged her to consider painting astronomical objects rather than studying them. Rubin was not deterred. “She took it all with courage, and with persistence,” says Bahcall, who was a longtime friend and colleague of Rubin.

Rubin studied astronomy at Vassar College, married mathematical physicist Bob Rubin, and began graduate school at Cornell in 1948. She completed her master’s thesis on the rotation of the universe, kicking off a long career investigating hidden galactic behavior, and a professor suggested Rubin present this research at a meeting of the American Astronomical Society (AAS) in 1950. There, she encountered a chilly reception. “I gave my memorized 10-minute talk, acceptably I thought. Then one by one many angry sounding men got up to tell me why I could not do ‘that,’” she wrote.
In 2019, almost 70 years after Rubin faced that hostile crowd at the 1950 AAS meeting, (and almost three years after her Death) the Society convened in Honolulu to agree on renaming the Large Synoptic Survey Telescope as the Vera C. Rubin Observatory. After its construction is complete, the Rubin Observatory will be the site of a 10-year survey of a mammoth swath of night sky. Bahcall sees this honor as the perfect tribute to Rubin, who cherished the many long nights she spent in observatories, peering through telescopes. “She loved being in the dome.” *APS Org





1930 Daniel McCracken, (July 23, 1930 – July 30, 2011) who wrote the first textbook on FORTRAN, was born. A student of mathematics and chemistry, McCracken started working in computers at General Electric in 1951, training workers in using the new technology. Based on this teaching experience, McCracken wrote several important computer programming textbooks, most notably ""A Guide to FORTRAN Programming"" in 1961.*CHM




1932 Derek Thomas "Tom" Whiteside FBA (July 23, 1932–April 22, 2008) was a British historian of mathematics. He was the foremost authority on the work of Isaac Newton and editor of The Mathematical Papers of Isaac Newton. From 1987 to his retirement in 1999, he was the Professor of the History of Mathematics and Exact Sciences at Cambridge University. *Wik




1941  Pierre Agostini (born 23 July 1941, ) is a French experimental physicist and Emeritus professor at the Ohio State University in the United States, known for his pioneering work in strong-field laser physics and attosecond science.He is especially known for the observation of above-threshold ionization and the invention of the reconstruction of attosecond beating by interference of two-photon transitions (RABBITT) technique for characterization of attosecond light pulses. He was jointly awarded the 2023 Nobel Prize in Physics with Ferenc Krausz and Anne L’Huillier. 



1952 Mark David Weiser (July 23, 1952 – April 27, 1999) American computer scientist and visionary who developed the pioneering idea for what he referred to as "ubiquitous computing," He coined that term in 1988 to describe a future in which PC's will be replaced with tiny computers embedded in everyday "smart" devices (everyday items such as coffeepots and copy machines) and their connection via a network. He said, "First were mainframes, each shared by lots of people. Now we are in the personal computing era, person and machine staring uneasily at each other across the desktop. Next comes ubiquitous computing, or the age of calm technology, when technology recedes into the background of our lives." *TIS







DEATHS

1876  Joseph Rogers Brown (born Jan. 26, 1810, Warren, R.I., U.S.—died July 23, 1876, Isles of Shoals, N.H.) was an American inventor and manufacturer who made numerous advances in the field of fine measurement and machine-tool production. He perfected and produced a highly accurate linear dividing engine in 1850, and in the succeeding two years he developed a vernier caliper reading to thousandths of an inch and also applied vernier methods to the protractor. Brown's micrometer caliper, widely used in industry, appeared in 1867. He also invented a precision gear cutter in 1855 to produce clock gears, a universal milling machine in 1862, and, perhaps his finest innovation, a universal grinding machine (patented in 1877), in which articles were hardened first and then ground, thereby increasing accuracy and eliminating waste. Cofounded J.R. Brown & Sharpe in 1853. *TiS

During the 19th and 20th centuries, Brown & Sharpe was one of the best-known and most influential machine tool builders and was a leading manufacturer of instruments for machinists (such as micrometers and indicators). Its reputation and influence were such that its name is often considered to be inseparably paired with certain industrial standards that it helped establish, including:


The American wire gauge (AWG) standards for wire;

The Brown & Sharpe taper in machine tool spindle tapers; and

The Brown & Sharpe worm threadform for worm gears.

Many years ago as a young Gauge Lab Tech I had a drawer full of these beauties in various sizes.  



1903 Eduard Weyr (22 June 1852 Praha – 23 July 1903 Záboří) wrote geometrical papers and books mainly in projective geometry and differential geometry. He also worked on algebra, in particular studying linear algebra, matrices and hypercomplex systems.
Weyr published Differential calculus in 1902. This led to controversy with a young mathematician J V Pexider who sharply criticised Weyr's textbook. Jindrich Beèváo and Ludek Zajièek give an interesting account of this episode in a paper in the book .*Math.info website



1916 William Ramsay (2 October 1852, Glasgow, Scotland - 23 July 1916 (aged 63)
High Wycombe, Bucks., England) died. Ramsay was a British chemist who discovered the four gases neon, argon, krypton and xenon. He also determined they belonged with helium and radon to form a family of gases called the noble gases. This discovery would earn him the 1904 Nobel Prize in Chemistry.*Science History



1932 Alberto Santos-Dumont (July 20, 1873 – July 23, 1932) was a Brazilian aviation pioneer, deemed the Father of Aviation by his countrymen. At the age of 18, Santos-Dumont was sent by his father to Paris where he devoted his time to the study of chemistry, physics, astronomy and mechanics. His first spherical balloon made its first ascension in Paris on 4 July 1898. He developed steering capabilities, and in his sixth dirigible on 19 Oct 1901 won the "Deutsch Prize," awarded to the balloonist who circumnavigated the Eiffel Tower. He turned to heavier-than-air flight, and on 12 Nov 1906 his 14-BIS airplane flew a distance of 220 meters, height of 6 m. and speed of 37 km/h. to win the "Archdecon Prize." In 1909, he produced his famous "Demoiselle" or "Grasshopper" monoplanes, the forerunners of the modern light plane. *TIS

Santos-Dumont circling the Eiffel Tower with the airship No. 5, 13 July 1901



1964 Samarendra Nath Roy or S. N. Roy (11 December 1906 – 23 July 1964). He was well known for his pioneering contribution to multivariate statistical analysis, mainly that of the Jacobians of complicated transformations for various exact distributions, rectangular coordinates and the Bartlett decomposition. His dissertation included the Post master's work at the Indian Statistical Institute where he worked under Mahalanobis. To commemorate his Birth Centenary an International Conference on "Multivariate Statistical Methods in the 21st Century: The Legacy of Prof. S.N. Roy" was held at Kolkata, India during December 28–29, 2006. The Journal of Statistical Planning and Inference published a special Issue for celebrating of the Centennial of Birth of S. N. Roy*Wik



1964 W. W. Rogosinski  (24 September 1894 – 23 July 1964) died. *VFR He wrote on Fourier Series with G.H. Hardy.  Rogosinski focused his studies on pure mathematics, physics and philosophy. His interest was analytical problems, especially in series. His dissertation, "New Application of Pfeiffer's method for Dirichlet's divisor problem", caused a stir in 1922.   

He published five papers with Hardy from 1943 to 1949, under the title Notes on Fourier series. In 1944 Rogisinski and Hardy published their book Fourier Series, which might be said to be a rewrite, using Lebesgue integral methods, of Rogosinski's 1930 book. He was a teacher in Aberdeen in 1941. In 1945, he became a lecturer at Newcastle University (prior to 1963, King's College, University of Durham). In 1947 he was appointed professor and in 1948 Head of Department.*Wik




1981 Harvey Fletcher (11 Sep 1884; 23 Jul 1981) American acoustical engineer who was the first to demonstrate stereophonic sound (1934). He was a trail blazing investigator of the nature of speech and hearing, noted for his contributions in acoustics, electrical engineering, speech, medicine, music, atomic physics, sound pictures, and education. He guided the development of the Western Electric Hearing Aid, the first such device to use vacuum tubes. He developed a group survey method using recorded sound of decreasing volume which has wide acceptance in schools throughout the nation.*TIS



1993 Florence Nightingale David, (August 23, 1909 – July 23, 1993) also known as F. N. David was an English statistician, born in Ivington, Herefordshire, England. She was named after Florence Nightingale, who was a friend of her parents.
David read mathematics at Bedford College for Women in London. After graduation, she worked for the eminent statistician Karl Pearson at University College, London as his research student. She calculated the distribution of correlation coefficients, producing in 1938 her first book, Tables of the correlation coefficient.
After Karl Pearson died in 1934, she returned to the Biometrics laboratory to work with Jerzy Neyman where she submitted her last four published papers as her PhD thesis. During World War II, David worked for the Ministry of Home Security. In late 1939 when war had started but England had not yet been attacked, she created statistical models to predict the possible consequences of bombs exploding in high density populations such as the big cities of England and especially London. From these models, she determined estimates of harm to humans and damage to non-humans This included the possible numbers living and dead, the reactions to fires and damaged buildings as well as damages to communications,utilities such as phones, water, gas, electricity and sewers. As a result when the Germans bombed London in 1940 and 1941, vital services were kept going and her models were updated and modified with the evidence from the real harms and real damage.
David became head of the Statistics Department at the University of California at Riverside in 1970.*Wik



2006  Charles Frederick Mosteller (December 24, 1916 – July 23, 2006) was an American mathematician, considered one of the most eminent statisticians of the 20th century. He was the founding chairman of Harvard's statistics department from 1957 to 1971, and served as the president of several professional bodies including the Psychometric Society, the American Statistical Association, the Institute of Mathematical Statistics, the American Association for the Advancement of Science, and the International Statistical Institute.
Mosteller worked in Samuel Wilks's Statistical Research Group in New York city during World War II on statistical questions about airborne bombing. He received his PhD in mathematics from Princeton University in 1946.

He was hired by Harvard University's Department of Social Relations in 1946, where he received tenure in 1951 and served as acting chair from 1953 to 1954. He founded the Department of Statistics and served as its first chairman from 1957 to 1969, 1973, 1975 to 1977. He chaired the Department of Biostatistics at the Harvard School of Public Health from 1977 to 1981 and later the Department of Health Policy and Management in the 1980s. His four chairmanships have not been matched. He also taught courses at Harvard Law School and Harvard's Kennedy School of Government.

He worked with his mathematical assistant Cleo Youtz from the 1950s until his departure from Harvard in 2003, and had an administrative assistant. He was well known for being a good writer, insisting on doing up to fifteen drafts of a paper or book chapter before showing it to his colleagues and several additional drafts before submitting the paper to a journal.

Mosteller was an elected member of the American Academy of Arts and Sciences (1954), the American Philosophical Society (1961), and the United States National Academy of Sciences (1974)] He retired from classroom teaching in 1987, but continued working and publishing at Harvard through 2003. On January 3, 2004, he moved to Arlington, Virginia, to be closer to his children. *Wik




2012  Sally Kristen Ride (May 26, 1951 – July 23, 2012) was an American physicist and a former NASA astronaut. Ride joined NASA in 1978, and in 1983 became the first American woman—and then-youngest American, at 32—to enter space. In addition to being interested in science, she was a nationally ranked tennis player. Ride attended Swarthmore College and then transferred to Stanford University, graduating with a bachelor's degree in English and physics. Also at Stanford, she earned a master's degree and a Ph.D. in physics, while doing research in astrophysics and free electron laser physics.In 1987 she left NASA to work at Stanford University's Center for International Security and Arms Control.
Sally Ride died on July 23, 2012 after a 17-month battle with pancreatic cancer.   US President Barack Obama called her a "national hero and a powerful role model" who "inspired generations of young girls to reach for the stars."*Wik





2021 Steven Weinberg (May 3, 1933 – July 23, 2021) American nuclear physicist who shared the 1979 Nobel Prize for Physics (with Sheldon Lee Glashow and Abdus Salam) for work in formulating the electroweak theory, which explains the unity of electromagnetism with the weak nuclear force. *TIS





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