Tuesday, 30 June 2026

On This Day in Math - August 1

   


Regarding all these basic topics in infinitesimal calculus which we teach today as canonical requisites ... the question is never raised, "Why so?" or "How does one arrive at them?" Yet all these matters must at one time have been goals of an urgent quest, answers to burning questions, at the time, namely, when they were created. If we were to go back to the origins of these ideas, they would lose that dead appearance of cut-and-dried facts and instead take on fresh and vibrant life again.
Otto Toeplitz - The calculus : A genetic approach (Chicago, 1963)


This is the 213th day of the year; 213 is a square free number as it has no repeated prime factors. How many days of the year are square free?

For 213, the sum of the digits and the product of the digits are equal, and forms a prime when one is added or subtracted.

The average prime factor of 213 is a prime number. [213 = 3*71 and (3+71)/2=37 ]

The square of 213 is a sum of distinct factorials: 2132 = 45369 = 1! + 2! + 3! + 7! + 8!, it is the smallest 3 digit number with this property. (what's next?)



EVENTS


1681, Michelangelo Ricci was made a cardinal by Pope Innocent XI.  Born in Rome in 1619, Ricci was educated in the tradition of rigorous Jesuit schooling, and he showed early promise in mathematics. He became closely associated with prominent mathematicians of the time, especially Evangelista Torricelli (the inventor of the barometer), whose works Ricci helped to preserve and promote after Torricelli’s death. Ricci moved in the same intellectual circles as Galileo Galilei and was involved in the post-Galilean scientific environment in Italy. 

  He studied theology and law in Rome, where he was a contemporary of René-François de Sluse. Sluse contributed to the development of calculus, focusing upon spirals, tangents, turning points and points of inflection. He and Johannes Hudde found algebraic algorithms for finding tangents, minima and maxima that were later utilized by Isaac Newton.

Ricci also studied mathematics under Benedetto Castelli who himself had been a student of Galileo Galilei.




1767 “Mason and Dixon finished drawing the world’s longest straight line.” [366 Dumb Days in History, by Tom Koch]

For those not familiar with the names and the line in question, "The Mason–Dixon line is a demarcation line separating four U.S. states, Pennsylvania, Maryland, Delaware and West Virginia. It was surveyed between 1763 and 1767 by Charles Mason and Jeremiah Dixon as part of the resolution of a border dispute involving Maryland, Pennsylvania, and Delaware in the colonial United States."

"Dixie, also known as Dixieland or Dixie's Land, is a nickname for all or part of the Southern United States. While there is no official definition of this region (and the included areas have shifted over the years), or the extent of the area it covers, most definitions include the U.S. states below the Mason–Dixon line that seceded and comprised the Confederate States of America, almost always including the Deep South. The term became popularized throughout the United States by songs that nostalgically referred to the American South."*Wik



In 1774, Joseph Priestley, British Presbyterian minister and chemist, identified a gas which he called "dephlogisticated air" -- later known as oxygen. Priestley found that mercury heated in air became coated with "red rust of mercury," which, when heated separately, was converted back to mercury with "air" given off. Studying this "air" given off, he observed that candles burned very brightly in it. Also, a mouse in a sealed vessel with it could breathe it much longer than ordinary air. A strong believer in the phlogiston theory, Priestley considered it to be "air from which the phlogiston had been removed." Further experiments convinced him that ordinary air is one fifth dephlogisticated air, the rest considered by him to be phlogiston. *TIS  

 Named from the Greek oxys + genes, "acid-former", oxygen was discovered in 1772 by  German-Sweedish chemist Carl Wilhelm Scheele  (although Joseph Priestley published his findings first) and independently by Priestly in 1774. Oxygen was given its name by the French scientist, Antoine Lavoisier.

Joseph Priestley



1786 Caroline Herschel discovered her first comet, Comet Herschel C/1786 P1 and became history's first woman with this distinction **(see below). Her comet came to be known as the "first lady's comet" and brought with it the fame that secured her own place in history books.*The Woman Astronomer
** The Renaissance Mathematicus pointed out in a blog that "Maria Margarethe Kirch (née Winkelmann), the wife of Gottfried Kirch the Astronomer Royal of Berlin, discovered the comet of 1702 (C/1702 H1) that is forty-eight years before Caroline Herschel was born. Unfortunately the discovery was published by her husband and it was he who was incorrectly acknowledged as the discoverer. In 1710 Gottfried admitted the error and publicly acknowledged Maria as the discoverer but she was never official credited with the discovery.
Both Maria Kirch and Caroline Herschel were excellent astronomers with much important work to their credit. However credit where credit is due, Caroline was not the first woman to discover a comet, Maria was."



1814 Almost a month after eloping with Georgiana Whitmore; a marriage of which his father did not approve, Charles Babbage writes to his friend John Herschel, who knew nothing of his secret romance, "I am married and have quarreled with my father." Then after a few lines of self-justification, he explains some theorems he has been working on. Herschel was shocked, and responded on the seventh of the same month.*Anthony Hyman, Charles Babbage: Pioneer of the Computer

Herschel responds six days later, ""I am married and I have quarreled with my father - Good God Babbage - How is it possible for a man to pen those two sentences, then ... pass off to functional expressions?" 


Charles Babbage and his "Engine"



In 1831, New London Bridge opened to traffic. In 1821, a committee was formed by Parliament to consider the poor condition of the existing centuries-old bridge. The arches had been badly damaged by the Great Freeze, so it was decided to build a new bridge. Building commenced under John Rennie in 1825, and completed in 1831, at the expense of the city. The bridge is composed of five arches, and built of Dartmoor granite. It was opened with great splendour by King William the fourth, accompanied by Queen Adelaide, and many of the members of the royal family, August 1st, 1831. In the 1960's it was auctioned and sold for $2,460,000 to Robert McCulloch who moved it to Havasu City, Arizona. The rebuilt London Bridge was completed and dedicated on 10 Oct 1971.*TIS




1861 First use of "weather forecast". From the BBC I read, "Telling people what had happened was useful, but not as useful as telling them what was going to happen. The man who made the first attempt to bridge that gap, and who coined the phrase "weather forecast", was Admiral Robert Fitzroy. Thirty years before, he had been captain of the Beagle voyage that carried Charles Darwin, so he was no stranger to the perils of weather when at sea. In 1854, Fitzroy was given the job of collecting data on weather at sea, leading what later became the Met Office. After a few years, he saw that weather systems could be tracked. He became convinced that predictions were possible and that storm warnings would save many lives. His bosses did not agree that predictions were realistic, but in spite of them Fitzroy started to issue storm warnings in 1861. Then, on the 1st of August 1861 (exactly 151 years ago), Fitzroy issued the first ever weather forecast for the general public, published in The Times. This earned him a slap on the wrist and a huge amount of criticism, because it was considered that the forecasts could not possibly be accurate. After a lot of debate, the public forecasts ended in 1866."   A tweet from @ Rebekah Higgitt corrected this to : weather predictions existed long before (including, but not only, astrological), but Aug 1861 *is* 1st use of term "weather forecast"..




1944 The MARK I computer began operation at Harvard. *VFR

The Harvard Mark I, or IBM Automatic Sequence Controlled Calculator (ASCC), was one of the earliest general-purpose electromechanical computers used in the war effort during the last part of World War II.

One of the first programs to run on the Mark I was initiated on 29 March 1944 by John von Neumann. At that time, von Neumann was working on the Manhattan Project, and needed to determine whether implosion was a viable choice to detonate the atomic bomb that would be used a year later. The Mark I also computed and printed mathematical tables, which had been the initial goal of British inventor Charles Babbage for his analytical engine in 1837. *Wik





1946 President Harry Truman signs the McMahon Act creating the Atomic Energy Commission.

* HT to Ben Gross ‏@bhgross144


1947 The Netherlands issued a postage stamp honoring Jans (Johan) de Witt (1625–1672), who did important early work dealing with analytic geometry. *VFR Besides being a statesman Johan de Witt, also was an accomplished mathematician. In 1659 he wrote "Elementa Curvarum Linearum" as an appendix to his translation of René Descartes' "La Géométrie". In this, De Witt derived the basic properties of quadratic forms, an important step in the field of linear algebra. *Wik


In 1957, the Solar Building (Bridgers and Paxton Office Building), Albuquerque NM, was the first commercial building to be heated by the sun's energy. It was subsequently listed in the National Register of Historic Places for its "exceptional importance," in the area of engineering because it was an early solar-heated commercial building, the equipment for which survived largely intact. It was constructed when active solar-energy systems were still considered experimental. The site is privately owned, at 213 Truman St., NE., Albuquerque, NM. The architectural design was provided by Wright and Stanley.*TIS



1963 Greece issued a postage stamp picturing the “Acropolis at Dawn” by Lord Baden-Powell.*VFR

To commemorate the realization of the 11th World Scout Jamboree in Greece, the Hellenic Post issued a special series of 5 stamps which circulated on August 1st, 1963, on the day the Jamboree officially opened.


1. DENOMINATION : 1 DRACHMA

“Athens at dawn”. A water-colour painted by Lord Baden-Powell of Gilwell in 1872, depicting the Acropolis and surrounding area. 2.5 million stamps of this denomination were circulated.






1967US Navy recalls Hopper to head COBOL effort.  The US Navy recalls Captain Grace Murray Hopper to active duty to help develop the programming language COBOL. With a team drawn from several computer manufacturers and the Pentagon, Hopper -- who had worked on the Mark I and II computers at Harvard in the 1940s -- created the specifications for COBOL (COmmon Business Oriented Language) with business uses in mind. These early COBOL efforts aimed at creating easily-readable computer programs with as much machine independence as possible. Designers hoped a COBOL program would run on any computer for which a compiler existed with only minimal modifications.
Hopper made many major contributions to computer science throughout her very long career, including what is likely the first compiler ever written, "A-0." She appears to have also been the first to coin the word "bug" in the context of computer science, taping into her logbook a moth which had fallen into a relay of the Harvard Mark II computer. She died on January 1, 1992.
The U.S. Navy commissioned their most advanced ship, the U.S.S. Hopper (DDG 70), on September 6, 1997 named in honor of Grace Hopper. *CMH

Log book showing the "bug" found caught in a Mark II relay




1980 Michael Aschbaher wrote Daniel Gorenstein that he had completed the classification of the finite simple groups. This culminated a 20-year effort by some 300 group theorists. The complete proof is about 5000 pages long. [Mathematics Magazine 54 (1981), p. 41



1986   Apple discontinues production of the Macintosh XL, effectively ending the life of the Apple Lisa computer platform. In January of 1985, the Macintosh line of computers was gaining momentum but the Lisa line of computers was not selling well. In order to salvage what they could from the Lisa and offer a more powerful Macintosh computer, Apple created the Macintosh XL model by modifying a Lisa 2/10 computer to run the Macintosh operating system. Apple discontinued the Lisa in April of 1985, but continued production of the hybrid Lisa/Mac Macintosh XL until this date. *This Day in Tech History



1987 The Italian Stronzo Bestiale appeared as a co-author in an erudite physics papers connecting fractal geometry, irreversibility, and the second law of thermodynamics,(Diffusion in a periodic Lorentz gas) along with the U.S. scientists Bill Moran and William G. Hoover. Until Bestiale joined them, the paper had been rejected. But Moran and Hoover had simply made this person up, and named him after hearing two Italian women on an aeroplane constantly referring to someone called “stronzo bestiale,”, which they discovered was not actually a person’s name, but meant “total asshole”. You can even get a T-shirt “I’m friends with Stronzo Bestiale”. *lenfisherscience


2011   Carolin Crawford selected as the Gresham Professor of Astronomy. *Wik

Crawford studied the Mathematical Tripos and received a Bachelor of Arts honours degree in mathematics at Newnham College, Cambridge in 1985. In 1988 she received her PhD[ for research undertaken at the Institute of Astronomy, Cambridge on cooling flows.

After her PhD, Crawford progressed through a series of postdoctoral and research fellowships at Balliol College, Oxford, the Institute of Astronomy, Trinity Hall, Cambridge and Newnham College, Cambridge. From 1996 to 2007 she held a Royal Society University Research Fellowship.

In 2004 she was appointed a Fellow and College Lecturer at Emmanuel College, Cambridge, where was also the undergraduate admissions tutor for the Physical Sciences. She held this position in conjunction with her role as Public Astronomer at the Institute of Astronomy, which she first took on in 2005.

She served as Gresham Professor of Astronomy at Gresham College from 2011 to 2015, a position in which she delivered free public lectures on astronomy and astrophysics in the City of London.

Crawford's "primary research interests are in combining X-ray, optical and near-infrared observations to study the physical processes occurring around massive galaxies at the core of clusters of galaxies. In particular, she observes the complex interplay between the hot intra-cluster medium, filaments of warm ionized gas, cold molecular clouds, star formation and the radio plasma flowing out from the central supermassive black hole.





BIRTHS



1662  Paul Halcke (also: Halcken or Halke), (1662 in Elmshorn, 1731 in Buxtehude was a German mathematician, writer, computer, and calendar maker.

He was the brother of writer and computer Johann Halcke and founded, in 1690, together with Heinrich Meißner, the Hamburgischen Kunst-Rechnungs lieb- und übenden Societät, today's Hamburg Mathematical Society. Since about 1687 he was writer and calculator at the city school of Buxtehude.

In 1694 he issued a solution's book to a collection of exercises by Heinrich Meißner, and later he published his own collection of 574 exercises from mathematics and astronomy, entitled Mathematischer Sinnen-Confect ("mathematical mind candy"), which was translated in various languages and remained a seminal textbook for more than a century. The exercises were enriched by poems and descriptions of the solving methods. In particular, exercise 289 on page 256 consists in finding the smallest Euler brick, for which Paul Halcke is most well-known today. This cuboid has sides and face diagonals of integer lengths {44, 117, 240} and {125, 244, 267}.

Halcken was also the first (1729) to show that  the product of the aliquot divisors of 24, equals its cube,         \(1*2*3*4*6*8*12 = 13824=24^3\)  and that the same fact is true about 40.

He also edited several popular calendars for the years 1705, 1707, 1715, 1716 and 1725.

An Euler brick, named after Leonhard Euler, is a rectangular cuboid whose edges and face diagonals all have integer lengths. A primitive Euler brick is an Euler brick whose edge lengths are relatively prime. A perfect Euler brick is one whose space diagonal is also an integer, but such a brick has not yet been found.



1817 Sir (Joseph) Henry Gilbert (1 August 1817 - 23 December 1901) English chemist who as co-director with John Bennet Lawes of the Rothamsted Experimental Station, Hertfordshire, for over 50 years established a premier reputation for research at the first organized agricultural experimental station in the world. Their work applied skills in chemistry, meteorology, botany, animal and vegetable physiology, and geology to determine practical improvements for agricultural methods. They studied the nitrogen requirements of plants, how the element was taken up by plants, and the effects of nitrogen fertilizers on grain production and quality. In the 1840s, they initiated the manufacture of superphosphate fertilizer, one of their inventions.*TIS




First Astronomy Class at Vassar College 1866

1818 Maria Mitchell (August 1, 1818 – June 28, 1889) First professional woman astronomer in the United States, born Nantucket, Mass. While pursuing an amateur interest, on 1 Oct 1847, she gained fame from the observation of a comet which she was first to report. She was also the first female member of the American Association of Arts and Scienes.
She became professor of astronomy at Vassar College in 1865, the first person (male or female) appointed to the faculty.  She was also named as Director of the Vassar College Observatory. After teaching there for some time, she learned that despite her reputation and experience, her salary was less than that of many younger male professors. She insisted on a salary increase, and got it. She taught at the college until her retirement in 1888, one year before her death.She died at age 70 in Lynn, Mass. *TIS




1861 Ivar Otto Bendixson (August 1, 1861 – 1935) taught at Stockholm, then from 1913 to 1927 he was rector of Stockholm University. He worked on set theory and differential equations. He is best remembered for the Poincaré - Bendixson theorem. *SAU



1881 Otto Toeplitz (1 August 1881, Breslau – 15 February 1940, Jerusalem) born in Breslau, Germany. In 1905 he received his Ph.D. in algebraic geometry at the university there and then moved to G¨ottingen, where he was deeply influenced by the work of Hilbert. He was also interested in the history of mathematics and held that only a mathematician of stature is qualified to be a historian of mathematics. In 1949 he published an introduction to the calculus on a historical basis. This delightful book is available in English as The Calculus. A Genetic Approach. *VFR



1905 Helen Battles (Sawyer) Hogg (1 Aug 1905, 28 Jan 1993) was a Canadian astronomer who located, cataloged and measured the distances to variable stars in globular clusters (stars with cyclical changes of brightness found within huge, dense conglomerations of stars located in the outer halo of the Milky Way galaxy). Her interest in astronomy was spurred when she witnessed a total eclipse of the sun in 1925. Alongside her career work, she was also foremost in Canada in popularizing astronomy, about which she wrote a column in the Toronto Star for thirty years. She was the first woman to become president of the Royal Canadian Institute. In 1989, the observatory at the National Museum of Science and Technology in Ottawa was dedicated in her name.*TIS



1913 Mischa Cotlar (August 1,1913, Sarny, Russian Empire – January 16, 2007, Buenos Aires, Argentina) was a mathematician who started his scientific career in Uruguay and worked most of his life on it in Argentina and Venezuela.


His contributions to mathematics are in the fields of harmonic analysis, ergodic theory and spectral theory. He introduced the Cotlar–Stein lemma. He was the author or co-author of over 80 articles in refereed journals.

According to Alberto Calderón, Cotlar showed in 1955 "that theorems on singular integrals can be generalized and put in the framework of ergodic theory." According to Krause, Lacey, and Wierdl, Karl E. Petersen in 1983 published an "especially direct proof" of Cotlar's 1955 theorem.

In January 1994 in Caracas, an international conference was held in his honor.*Wik



1924 Georges Charpak (1 August 1924 – 29 September 2010) was a French physicist who was awarded the Nobel Prize in Physics in 1992 "for his invention and development of particle detectors, in particular the multiwire proportional chamber". This was the last time a single person was awarded the physics prize. *Wik



1937 Barry Edward Johnson (1 Aug 1937 Woolwich, London, England – 5 May 2002 Newcastle upon Tyne, England) is well known for his work on Banach algebras and operator algebras, in particular, studying cohomology in these algebras. His mathematical publications started in 1964 with a series of papers on topological algebras, measure algebras and Banach algebras. In these he examined the theory of centralizers and the continuity of transformations. In 1964 he wrote a joint paper with Ringrose Derivations of operator algebras and discrete group algebras and his next papers continued to examine the continuity of homomorphisms, derivations and linear operators. He developed cancer on February 2000 and fought the disease bravely. Despite his deteriorating physical condition, he continued to undertake cutting edge mathematical research. He died of cancer in St Oswald's Hospital in Newcastle upon Tyne aged 64. *SAU



1945 Douglas Dean Osheroff (born August 1, 1945) is an American physicist who shared with David M. Lee and Robert Richardson) was the corecipient of the 1996 Nobel Prize for Physics for their discoveryof superfluidity in the isotope helium-3. As helium is reduced in temperature toward almost absolute zero, a strange phase transition occurs, and the helium takes on the form of a superfluid. The atoms had until that point had moved with random speeds and directions. But as a superfluid, the atoms then move in a co-ordinated manner! *TiS, *Wik



1955 Bernadette Perrin-Riou (August 1, 1955 - ) was awarded the 1999 Ruth Lyttle Satter Prize in recognition of her number theoretical research on p-adic L-functions and Iwasawa theory.

A French number theorist whose parents had both had a scientific education; her mother and father were a physicist and chemist, respectively. She was brought up, along with her sisters, in Neuilly-sur-Seine.

She became maître de conferences at UPMC in 1983, and was then invited to spend a year as a visiting professor at Harvard University; she subsequently became a professor at the same university.

In 1994 she moved to a position at University of Paris-Sud in Orsay. In the same year, she was invited to give an address at the International Congress of Mathematicians, which was held in Zürich, which she gave on "Fonctions L p-adiques" ("p-adic L-functions"). *Wik




1970 Elon Lindenstrauss (August 1, 1970 - ) was the first Israeli to be awarded the Fields Medal, for his results on measure rigidity in ergodic theory, and their applications to number theory.
Since 2004, he has been a professor at Princeton University. In 2009, he was appointed to Professor at the Mathematics Institute at the Hebrew University.
Lindenstrauss is the son of the mathematician Joram Lindenstrauss, the namesake of the Johnson–Lindenstrauss lemma, and computer scientist Naomi Lindenstrauss, both professors at the Hebrew University.
Lindenstrauss was awarded the Erdős Prize and the Fermat Prize in 2009. *Wik





DEATHS

1630 Federico Cesi (13 Mar 1585; 1 Aug 1630 at age 45) Italian scientist who founded the Accademia dei Lincei (1603, Academy of Linceans or Lynxes), often cited as the first modern scientific society, and of which Galileo was the sixth member (1611). Cesi first announced the word telescope for Galileo's instrument. At an early age, while being privately educated, Cesi became interested in natural history and that believed it should be studied directly, not philosophically. The name of the Academy, which he founded at age 18, was taken from Lynceus of Greek mythology, the animal Lynx with sharp sight. He devoted the rest of his life to recording, illustrating and an early classification of nature, especially botany. The Academy was dissolved when its funding by Cesi ceased upon his sudden death(at age 45). *TIS It was revived in its currently well known form of the Pontifical Academy of Sciences, by the Vatican, Pope Pius IX in 1847.




1896 Sir William Robert Grove, (11 July 1811 – 1 August 1896) British physicist and a justice of Britain's high court (from 1880), who first offered proof of the thermal dissociation of atoms within a molecule. He showed that steam in contact with a strongly heated platinum wire is decomposed into hydrogen and oxygen in a reversible reaction. In 1839, Grove mixed hydrogen and oxygen in the presence of an electrolyte, and produced electricity and water. This Grove Cell was the invention of the fuel cell. The technology was not seriously revisited until the1960s. Through the electrochemical process, the energy stored in a fuel is converted - without combusting fuel - directly into DC electricity.*TIS




1920 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. 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




1904 Adolf Lindenbaum (12 June 1904 – ? August 1941) was a Polish-Jewish logician and mathematician best known for Lindenbaum's lemma and Lindenbaum–Tarski algebras.

He was born and brought up in Warsaw. He earned a Ph.D. in 1928 under Wacław Sierpiński and habilitated at the University of Warsaw in 1934. He published works on mathematical logic, set theory, cardinal and ordinal arithmetic, the axiom of choice, the continuum hypothesis, theory of functions, measure theory, point-set topology, geometry and real analysis. He served as an assistant professor at the University of Warsaw from 1935 until the outbreak of war in September 1939. He was Alfred Tarski's closest collaborator of the inter-war period. Around the end of October or beginning of November 1935 he married Janina Hosiasson, a fellow logician of the Lwow–Warsaw school. He and his wife were adherents of logical empiricism, participated in and contributed to the international unity of science movement, and were members of the original Vienna Circle. Sometime before the middle of August 1941 he and his sister Stefanja were shot to death in Naujoji Vilnia (Nowa Wilejka), 7 km east of Vilnius, by the occupying German forces or Lithuanian collaborators



1987 Evelyn Merle Nelson (November 25, 1943 – August 1, 1987), born Evelyn Merle Roden, was a Canadian mathematician. Nelson made contributions to the area of universal algebra with applications to theoretical computer science. Nelson's teaching record was, according to one colleague, "invariably of the highest order". However, before earning a faculty position at McMaster, prejudice against her lead to doubts about her teaching ability. Nelson published over 40 papers during her 20-year career before she died from cancer in 1987.
She, along with Cecilia Krieger, is the namesake of the Krieger–Nelson Prize, awarded by the Canadian Mathematical Society for outstanding research by a female mathematician. *Wik




1992 Leslie Fox (September 1918 Dewsbury, Yorkshire-1 August 1992 Oxford) was a British Mathematician noted for his contribution to numerical analysis.
Fox studied mathematics as a Scholar of Christ Church, Oxford graduating with a First in 1939 and continued to undertake research in the engineering department. While working on his D.Phil. in computational and engineering mathematics under the supervision of Sir Richard Southwell he was also engaged in highly secret war work. He worked on the numerical solution of partial differential equations at a time when numerical linear algebra was performed on a desk calculator. Computational efficiency and accuracy was thus even more important than in the days of electronic computers. Some of this work was published after the end of the Second World War jointly with his supervisor Richard Southwell.
On gaining his doctorate in 1942 Fox joined the Admiralty Computing service. Following the war, in 1945 he went to work in the mathematics division of the National Physical Laboratory. He left the National Physical Laboratory in 1956 and spent a year at the University of California. In 1957 Fox took up an appointment at Oxford University where he set up the Computing Laboratory. In 1963 Fox was appointed as Professor of Numerical Analysis at Oxford and Fellow of Balliol College, Oxford.
Fox's laboratory at Oxford was one of the founding organisations of the Numerical Algorithms Group, and Fox was also a dedicated supporter of the Institute of Mathematics and its Applications (IMA). The Leslie Fox Prize for Numerical Analysis of the IMA is named in his honour.*Wik


1996 Tadeusz Reichstein (20 July 1897 – 1 August 1996) was a Polish-born Swiss chemist, botanist and Nobel laureate.

Reichstein, with Philip S. Hench and Edward C. Kendall, received the Nobel Prize for Physiology or Medicine in 1950 for his discoveries concerning hormones of the adrenal cortex, their structure and biological effects. With his co-workers, Reichstein accomplished the first isolation of four active hormones from the adrenal cortex, the first synthesis of one of them, the proof of the steroid nature of said hormones, and numerous details on the structure and properties of these important bodies. This made synthesis possible, leading to the creation of new medications *TiS *Wik 




1999 Marie Paris Pişmiş de Recillas (30 January 1911 – 1 August 1999) was an Armenian-Mexican astronomer.

Pişmiş was born Mari Sukiasian (Armenian: Մարի Սուքիասեան) in 1911, in Ortaköy, Istanbul. She completed her high school studies at Üsküdar American Academy. In 1937, she became the first woman to get a Ph.D. from the Science Faculty of Istanbul University. Her advisor was Erwin Finlay Freundlich. Later, she went to Harvard University where she met her future husband Félix Recillas, a Mexican mathematician. They settled in Mexico, and she became the first professional astronomer in Mexico. According to Dorrit Hoffleit, "she is the one person most influential in establishing Mexico’s importance in astronomical education and research".

For more than 50 years she worked at UNAM which awarded her a number of prizes including the "Science Teaching Prize". She was a member of the Mexican Academy of Sciences.

Pişmiş studied among others the kinematics of galaxies, H II nebulae, the structure of open star clusters and planetary nebulae. She compiled the catalogue Pismis of 24 open clusters and 2 globular clusters in the southern hemisphere.

In 1998, she published an autobiography entitled "Reminiscences in the Life of Paris Pişmiş: a Woman Astronomer". She died in 1999. According to her wish, she was cremated. Her daughter Elsa Recillas Pishmish, son-in-law Carlos Cruz-González, and grand-daughter Irene Cruz-González also became astronomers. *Wik




2004 Philip Hauge Abelson (April 27, 1913 – August 1, 2004) was an American physicist, scientific editor and science writer. He proposed the gas diffusion process for separating uranium-235 from uranium-238 which was essential to the development of the atomic bomb. In collaboration with the U.S. physicist Edwin M. McMillan, he discovered a new element, later named neptunium, produced by irradiating uranium with neutrons. At the end WW II, his report on the feasibility of building a nuclear-powered submarine gave birth to the U.S. program in that field. In 1946, Abelson returned to the Carnegie Institution and pioneered in utilizing radioactive isotopes. As director of the Geophysics Laboratory of the Carnegie Institution (1953-71), he found amino acids in fossils, and fatty acids in rocks more than 1,000,000,000 years old. *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

On This Day in Math - June 30

   

You know we all became mathematicians for the same reason: 
we were lazy. 

Max Rosenlicht

The 181st day of the year; 181 is the 9th palindromic prime number.

1f you square 181 and add 7, you get 32768.  So what? Well 32768 is 215.  STILL not impressed?  The only other numbers for which n2 + 7 is a power of 2 are 1, 3, 5, and 11.... full stop.  And to take this beyond the coincidental, if you replace the 7 with any other integer, there will never be more than two solutions.

and the 181-digit palindromic number made up of all 7's except for the center being 181 (7777...7718177...77777) is a palindromic prime with a palindromic prime decimal length.

181 is the both the difference and the sum of consecutive squares:
\( 181 = 91^2 – 90^2 = 9^2 + 10^2 \)

 Every natural number greater than 181 can be written as sum of cubes of the first two primes. (students might be asked to find all examples of numbers less than 181 that can be written in this fashion, such as 35= 23 + 33)

More Math Facts for every year day here.




EVENTS

1601.  Johannes Kepler  uses a camera obscura of his own design set up in a tent to view solar eclipses in Graz on 30 June 1601 . Infamously whilst he was busy observing the solar eclipse on the market place in Graz  a thief stole his purse with thirty silver florins. It was Kepler that coined the name camera obscura. The earliest use of the term "camera obscura" is found in his 1604 book, Ad Vitellionem Paralipomena.*RMAT Art Historian J V Field has suggested that in the same book he invented two other math/science ideas: "The two inventions in question are the point at infinity’ and the retinal image. The first is apparently merely mathematical whereas the second is certainly conceived as having physical existence, but the two processes of invention are both closely bound up with Kepler’s conception of the role of mathematical reasoning in natural philosophy, and they consequently have much in common. "

Camera Obscura design of Gemma Frisius,16th C




1668     Prince Cosimo's assistant Bassetti writes to  Samuel Morlands agent for his arithmetic machines to request the purchase of one.  "The Prince has heard that a man named Samuel Morland,.., has invented an instrument that is similar to a box of occhiali (glass lenses) which is made in such a way that when you round some circles it is possible to see immediately  the result of some reasoning or mathematical calculation. If this is true, the Prince wants one of those."    
A calculator was sent for the advertised English price of three pounds , ten shillings.  It may be that Morland actually reconfigured his calculator from pounds,shillings,pence to base four scudo.  It is not clear if this Morland-type machine was a gift from Morland, or an Italian made machine copying Morland's technique.  






1686 The Royal Society made the decision to publish De Historia Piscium, a lavishly-illustrated history of fishes by John Ray and Francis Willughby. The books was beautiful, but turned out to be such a poor seller that the Society almost went bankrupt. At one point Edmond Halley's salary could not be paid during the same period when he was trying to get Newton to complete his epic masterpiece, The Principia. Fortunately for science, Halley accepted a deal for something like one-hundred copies of the fish book, and then mostly funded the publication of Newton's classic himself over the next year. I don't know if Halley ever managed to sell any of the De Historia Piscium that he took in lieu of salary. *PB old notes.

1737 John Harrison, after positive results on the test of his first sea-clock, receives the first money awarded by the Board of Longitude (23 years after the Act to create the Board). Harrison received 500 Pounds, 250 Pounds to be paid immediately, and another 250 Pounds after completing a second clock that passes testing at sea. *Derek Howse, Britain's Board of Longitude: The Finances 1714-1828
Harrison's H2



1742 Euler replied (see June 7 post) in a letter dated 30 June 1742, and reminded Goldbach of an earlier conversation they had ("...so Ew vormals mit mir communicirt haben.."), in which Goldbach remarked his original (and not marginal) conjecture followed from the following statement, “Every even integer greater than 2 can be written as the sum of two primes,” which is thus also a conjecture of Goldbach. In the letter dated 30 June 1742, Euler stated:“Dass ... ein jeder numerus par eine summa duorum primorum sey, halte ich für ein ganz gewisses theorema, ungeachtet ich dasselbe necht demonstriren kann.” ("every even integer is a sum of two primes. I regard this as a completely certain theorem, although I cannot prove it.")*Wik
As of this date, no one else has proved it either. It is one of the oldest open questions in mathematics.
Euler also claimed that prime numbers of the form 4n+ 1 are represented uniquely as a sum of two squares. He also mentions that 641 divides 232 + 1, thereby disproving Fermat’s claim that all numbers Fermat numbers F(n)= \( 2^{2^n}+1\) are prime. Years later we have not found another which is prime.



1812 Congress authorized the President of the US to issue interest bearing Treasury Notes for the first time in history.  The interest was fixed at "five and two-fifths per centum a year."  *Kane, Famous First Facts (students might calculate the present value of a $100 investment on that date compounded to the present)

1808 Sir Humphrey Davy announced the discovery of magnesium (Mg), calcium (Ca), strontium (Sr) and barium (Ba) on this day in 1808
Throughout his career Davy isolated several metal elements from their compounds through the process of electrolysis, using a primitive electrical battery called a voltaic pile.
Davy also announced he had separated the element boron. However, working independently, French chemist, Joseph Louis Gay-Lussac had announced* the same accomplishment nine days earlier, on 21 Jun 1808.  *TIS
Davy Statue, Penzance



1860 Oxford evolution debate took place at the Oxford University Museum on 30 June 1860, seven months after the publication of Charles Darwin's On the Origin of Species. Several prominent British scientists and philosophers participated, including Thomas Henry Huxley, Bishop Samuel Wilberforce, Benjamin Brodie, Joseph Dalton Hooker and Robert FitzRoy.
The debate is best remembered today for a heated exchange in which Wilberforce supposedly asked Huxley whether it was through his grandfather or his grandmother that he claimed his descent from a monkey. Huxley is said to have replied that he would not be ashamed to have a monkey for his ancestor, but he would be ashamed to be connected with a man who used his great gifts to obscure the truth *Wik
T H Huxley, Darwin's Bulldog



1894 Tower Bridge opens, In 1886, the foundation stone of the Tower Bridge in London, England was laid (over a time capsule) by the Prince of Wales. The need to cross the River Thames at this point had become increasingly urgent for many years, and finally the necessary Act was passed in 1885. The bridge, designed by Mr. Wolfe Barry, CB, was completed at a cost of about £1,000,000. To permit the passage of tall ships between the towers, two bascule spans, each of 100-ft length, are raised. The side spans to the towers are of the more familiar suspension type. Pedestrians can traverse a high-level footway nearly at the top of the towers, even when the bridge is raised. It was officially opened 30 Jun 1894, by the Prince of Wales, later Edward VII, on behalf of Queen *TIS



1905 Albert Einstein's paper, "On the electrodynamics of moving bodies" (special relativity) is received at the Journal Annalen der Physik.
"Einstein develops the special theory of relativity in this paper. His concern, as he makes clear in the introduction, is that then current electrodynamics harbors a state of rest, the ether state of rest, and the theory gives very different accounts of electrodynamic processes at rest or moving in the ether. But experiments in electrodynamics and optic have provided no way to determine which is the ether state of rest of all inertial state of motion. Einstein shows that Maxwell-Lorentz electrodynamics has in fact always obeyed a principle of relativity of inertial motion. We just failed to notice it since we tacitly thought that space and time had Newtonian properties, not those of special relativity. " *John D Norton, Einstein, 1905, Pitt.edu



1908 A Comet(?) explodes above Tunguska, Siberia. *VFR In 1908, at around 7:15 am, northwest of Lake Baikal, Russia, a huge fireball nearly as bright as the Sun was seen crossing the sky. Minutes later, there was a huge flash and a shock wave felt up to 650 km (400 mi) away. Over Tunguska, a meteorite over 50-m diameter, travelling at over 25 km per second (60,000 mph) penetrated Earth's atmosphere, heated to about 10,000 ºC and detonated 6 to10 km above the ground. The blast released the energy of 10-50 Megatons of TNT, destroying 2,200 sq km of forest leaving no trace of life. The Tunguska rock came out of the Taurid Meteor storm that crosses Earth's orbit twice a year. The first scientific expedition for which records survive was made by Russian mineralogist Leonid Kulik in 1927. *TIS 



1945 The first distribution of John von Neumann's First Draft of a Report on the EDVAC, containing the first published description of the logical design of a computer with stored-program and instruction data stored in the same address space within the memory (von Neumann architecture)*Wik

1946 ENIAC formally accepted by the government. See 2 October 1955*VFR

1948 Encouraged by Executive Vice President Mervin Kelly, William Shockley returned from wartime assignments in early 1945 to begin organizing a solid-state physics group at Bell Labs. Among other things, this group pursued research on semiconductor replacements for unreliable vacuum tubes and electromechanical switches then used in the Bell Telephone System. That April he conceived a "field-effect" amplifier and switch based on the germanium and silicon technology developed during the war, but it failed to work as intended. A year later theoretical physicist John Bardeen suggested that electrons on the semiconductor surface might be blocking penetration of electric fields into the material, negating any effects. With experimental physicist Walter Brattain, Bardeen began researching the behavior of these "surface states."

On December 16, 1947, their research culminated in the first successful semiconductor amplifier. Bardeen and Brattain applied two closely-spaced gold contacts held in place by a plastic wedge to the surface of a small slab of high-purity germanium. The voltage on one contact modulated the current flowing through the other, amplifying the input signal up to 100 times. On December 23 they demonstrated their device to lab officials - in what Shockley deemed "a magnificent Christmas present."

Named the "transistor" by electrical engineer John Pierce, Bell Labs publicly announced the revolutionary solid-state device at a press conference in New York on June 30, 1948. A spokesman claimed that "it may have far-reaching significance in electronics and electrical communication." Despite its delicate mechanical construction, many thousands of units were produced in a metal cartridge package as the Bell Labs "Type A" transistor.
*CHM


1954 Solar eclipse in Britain. The about 3 minutes totality was visible in the Faroes and the southern line was crossing the northernmost Shetland. Many people in England do remember this eclipse and is often mistaken as total for those who saw a large partial eclipse. The eclipse track traveled across Norway, Sweden, Lithuania, Byelorussia, and Russia. *NSEC

1955 Sperry Rand formed. In 1955 Sperry acquired Remington Rand and renamed itself Sperry Rand. Acquiring then Eckert-Mauchly Computer Corporation and Engineering Research Associates along with Remington Rand, the company developed the successful UNIVAC computer series and signed a valuable cross-licensing deal with IBM. *Wik

1972 The International Time Bureau adds the first leap second to Coordinated Universal Time (UTC).
A leap second is a one-second adjustment that is occasionally applied to Coordinated Universal Time (UTC), to accommodate the difference between precise time (International Atomic Time (TAI), as measured by atomic clocks) and imprecise observed solar time (UT1), which varies due to irregularities and long-term slowdown in the Earth's rotation. The UTC time standard, widely used for international timekeeping and as the reference for civil time in most countries, uses TAI and consequently would run ahead of observed solar time unless it is reset to UT1 as needed. The leap second facility exists to provide this adjustment. The leap second was introduced in 1972. Since then, 27 leap seconds have been added to UTC, with the most recent occurring on December 31, 2016. *Wik 
Graph showing the difference between UT1 and UTC. Vertical segments correspond to leap seconds.








    

1973 A group of scientist boarded a prototype French Concorde airplane to chase a solar eclipse. The eclipse promised a luxurious view if you stood at the right place on the planet: a maximum of 7 minutes and 4 seconds as the moon passed over the Sahara Desert. It would be just 28 seconds short of the longest possible eclipse viewable from Earth; in the preceding several hundred years, there had only been one eclipse longer than this one, and there would not be a longer total solar eclipse until June 2150. Not satisfied with one of the longest eclpises in recent history, the group managed to negotiate a viewing flight on the still in testing Concorde. Closing in at maximum velocity, Concorde would swoop down from the north and intercept the shadow of the moon over northwest Africa. Traveling together at almost the same speed, Concorde would essentially race the solar eclipse across the surface of the planet, giving astronomers an unprecedented opportunity to study the various phenomena made possible by an eclipse. In one flight, Concorde had given astronomers more eclipse observing time than all the previous expeditions last century—generating three articles in Nature and a wealth of new data. *Motherboard


2011 Mr Ballew finally hung up his spurs and rode off into the sunset with his sweetheart, Jeannie.






2015 A Leap second is added to the clock in the last second before 8pm, so there will be a minute with 61 seconds. Between 1972 and 2012, a leap second has been inserted about every 18 months, on average. However, the spacing is quite irregular and apparently increasing: there were no leap seconds in the seven-year interval between January 1, 1999 and December 31, 2005, but there were nine leap seconds in the eight years 1972–1979. Another was added the next year.*Wik


BIRTHS

1748  Dominique Cassini (30 June 1748 – 18 October 1845)  was a French mathematician and surveyor who worked on his father's map of France.  He was the son of César-François Cassini de Thury and was born at the Paris Observatory. In 1784 he succeeded his father as director of the observatory; but his plans for its restoration and re-equipment were wrecked in 1793 by the animosity of the National Assembly. His position having become intolerable, he resigned on September 6, and was thrown into prison in 1794, but released after seven months. He then withdrew to Thury, where he died fifty-one years later.
He published in 1770 an account of a voyage to America in 1768, undertaken as the commissary of the French Academy of Sciences with a view to testing Pierre Le Roy’s watches at sea. A memoir in which he described the operations superintended by him in 1787 for connecting the observatories of Paris and Greenwich by longitude-determinations appeared in 1791. He visited England for the purposes of the work, and saw William Herschel at Slough. He completed his father’s map of France, which was published by the Academy of Sciences in 1793. It served as the basis for the Atlas National (1791), showing France in departments.
Cassini’s Mémoires pour servir à l’histoire de l’observatoire de Paris (1810) embodied portions of an extensive work, the prospectus of which he had submitted to the Academy of Sciences in 1774. The volume included his Eloges of several academicians, and the autobiography of his great-grandfather, Giovanni Cassini.*Wik



1791  Félix Savart (June 30, 1791, Charleville-Mézières, Ardennes – March 16, 1841, Paris) became a professor at Collège de France in 1836 and was the co-originator of the Biot-Savart Law, along with Jean-Baptiste Biot. Together, they worked on the theory of magnetism and electrical currents. Their law was developed about 1820. The Biot-Savart Law relates magnetic fields to the currents which are their sources. Félix Savart also studied acoustics. He developed the Savart wheel which produces sound at specific graduated frequencies using rotating disks.
Félix Savart is the namesake of the unit of measurement for musical intervals, the savart, though it was actually invented by Joseph Sauveur.*Wik



1856 Cargill Knott (June 30, 1856 – October 26, 1922) born. He graduated from Edinburgh University and was then an assistant in the Physics department. With Barclay and Fraser he was one of the writers who originally proposed the founding of the EMS. He went to the Imperial University in Tokyo as Professor. He was a pioneer in seismological research and undertook the first geomagnetic survey of Japan, assisted by Japanese geophysicist Tanakadate Aikitsu, from which was developed the first earthquake hazard map of Japan. Knott's key contribution was his background in mathematics and data analysis. One of his innovations was to apply the technique of Fourier analysis to the occurrence of earthquakes. Two chapters in his 1908 book The Physics of Earthquake Phenomena were devoted to this subject, which Knott hoped would enable him to deduce the probability of when future earthquakes would occur.
He returned to a lectureship in Edinburgh and eventually became a Reader in Applied Mathematics. and became Secretary and Treasurer of the EMS in 1883 and President in 1893 and 1918.*SAU



1880 Rudolf Fueter (30 June 1880 in Basel; 9 August 1950 in Brunnen) who worked with functions with non-commutative variables and also in number theory. *SAU  
Fueter did research on algebraic number theory and quaternion analysis proposing a definition of ‘regular’ for quaternionic functions similar to the definition of holomorphic function by means of an analogue of the Cauchy-Riemann equations] He also published a proof of the Fueter–Pólya theorem with George Pólya.

In 1910 he was one of the founders of the Swiss Mathematical Society and he became its first president. With Andreas Speiser he was instrumental in the editing and publication of the collected works of Leonhard Euler and from 1927 he was the head of the Euler Commission. He gave plenary lectures at the International Congress of Mathematicians in 1932 at Zurich (Idealtheorie und Funktionentheorie) and in 1936 at Oslo (Die Theorie der regulären Funktionen einer Quaternionenvariablen). *Wik
Rudolf Fueter (2nd from right) at the International Congress of Mathematicians, Zürich 1932
The woman to his right was Dorothy Winch. Ske  was Girton's only Wrangler in 1916. The 'Manchester Guardian' published the names of all the Wranglers, hers included, but biographies only of the men. A mathematician and biochemical theorist best known for her attempt to deduce protein structure using mathematical principles. She was a champion of the controversial 'cyclol' hypothesis for the structure of proteins.





 1907 Dmitry Konstantinovich Faddeev (30 June 1907 – 20 October 1989) was a Soviet mathematician.
In 1928 he graduated from Petrograd State University, as it was then called. His teachers included Ivan Matveyevich Vinogradov and Boris Nicolaevich Delone. In 1930 he married Vera Nicolaevna Zamyatina (Faddeeva). They had three children, including the mathematical physicist Ludvig Faddeev.
Dmitry Faddeev's students included Mark Bashmakov (ru), Zenon Borevich, Lyudmyla Nazarova, Andrei Roiter, Alexander Skopin, and Anatoly Yakovlev (ru).
D. K. Faddeev and V. N. Faddeeva co-authored Numerical Methods in Linear Algebra in 1960, followed by an enlarged edition in 1963. For instance, they developed an idea of Urbain Leverrier to produce an algorithm to find the resolvent matrix 
 (A-sI)^{-1}} of a given matrix A. By iteration, the method computed the adjugate matrix and characteristic polynomial for A.
Dmitry was committed to mathematics education and aware of the need for graded sets of mathematical exercises. With Iliya Samuilovich Sominskii he wrote Problems in Higher Algebra.
He was one of the founders of the Russian Mathematical Olympiads. He was one of the founders of the a Physics-Mathematics secondary school later named after him. *Wik 




1923 Alexander Murray Macbeath (30 June 1923 Glasgow – 14 May 2014 Warwick)was a mathematician who worked on Riemann surfaces. Macbeath surfaces and Macbeath regions are named after him.
During World War II, he worked in Hut 7 of the Government Code and Cypher School at Bletchley Park, breaking ciphers used for military communications by the Japanese navy and, later, the army.

After the war he earned an M.A. (again with honours) from Clare College, Cambridge. With a Commonwealth Fund fellowship, he then attended Princeton University, where he earned his Ph.D. in 1950 under the supervision of Emil Artin.
He taught at Keele University and the University of Dundee before moving to the University of Birmingham in 1963 where he stayed until 1979 as Mason Professor, then moved back to the University of Pittsburgh in the United States until he reached their statutory retirement age of 60.

He subsequently took up a position at the University of Dundee where he remained for a number of years, before moving to Warwickshire where at the University of Warwick he held the position of Emeritus Professor of Mathematics.*Wik
Murray Macbeath (right) with Wilhelm Kaup




1958 Abigail A. Thompson (June 30, 1958 in Norwalk, Connecticut) is an American mathematician. She works as a professor of mathematics at the University of California, Davis, where she specializes in knot theory and low-dimensional topology. Thompson extended David Gabai's concept of thin position from knots to 3-manifolds and Heegaard splittings.
Thompson graduated from Wellesley College in 1979, and earned her Ph.D. in 1986 from Rutgers University under the joint supervision of Martin Scharlemann and Julius L. Shaneson. After visiting positions at the Hebrew University of Jerusalem and the University of California, Berkeley, she joined the University of California Davis faculty in 1988. Thompson had a postdoctoral fellowship with the National Science Foundation from 1988 to 1991 and a Sloan Foundation Fellowship from 1991 to 1993. She was a member of the Institute for Advanced Study in 1990-1991, 2000-2001, and 2015-2016. She became the Chair of the Department of Mathematics at UC Davis in 2017. She is one of the current vice presidents of the American Mathematical Society; her term is February 1, 2019 to January 31, 2022.
Thompson has also been an activist for reform of primary and secondary school mathematics education. She has publicly attacked the Mathland-based curriculum in use in the mid-1990s when the oldest of her three children began studying mathematics in school, claiming that it provided an inadequate foundation in basic mathematical skills, left no opportunity for independent work, and was based on poorly written materials. As an alternative, she founded a program at UC Davis to improve teacher knowledge of mathematics, and became the director of the California State Summer School for Mathematics and Science, a month-long summer mathematics camp for high school students. *Wik











DEATHS

1660 William Oughtred, (5 March 1575 – 30 June 1660) inventor of the slide rule (1621) and a staunch royalist, died in a transport of joy on hearing the news of the restoration of Charles II. Augustus De Morgan later remarked, “It should be added, by way of excuse, that he was eighty-six years old.” *VFR an Episcopal minister who invented the earliest form of the slide rule, two identical linear or circular logarithmic scales held together and adjusted by hand. Improvements involving the familiar inner rule with tongue-in-groove linear construction came later. He introduced the familiar multiplication sign x in a 1631 textbook, along with the first use of the abbreviations sin, cos and tan.*TIS





1919 John William Strutt 3rd Baron of Rayleigh (of Terling Place)(12 November 1842 – 30 June 1919) was an English physical scientist who made fundamental discoveries in the fields of acoustics and optics that are basic to the theory of wave propagation in fluids. He received the Nobel Prize for Physics in 1904 for his investigations into the densities of the most important gases and his successful isolation of argon, an inert atmospheric gas.*TIS
He spent all of his academic career at the University of Cambridge.  He served as president of the Royal Society from 1905 to 1908 and as chancellor of the University of Cambridge from 1908 to 1919.
Rayleigh provided the first theoretical treatment of the elastic scattering of light by particles much smaller than the light's wavelength, a phenomenon now known as "Rayleigh scattering", which notably explains why the sky is blue. *Wik



 

 1961 Lee de Forest (August 26, 1873 – June 30, 1961) was an American inventor and a fundamentally important early pioneer in electronics. He invented the first practical electronic amplifier, the three-element "Audion" triode vacuum tube in 1906. This helped start the Electronic Age, and enabled the development of the electronic oscillator. These made radio broadcasting and long distance telephone lines possible, and led to the development of talking motion pictures, among countless other applications.
He had over 300 patents worldwide, but also a tumultuous career – he boasted that he made, then lost, four fortunes. He was also involved in several major patent lawsuits, spent a substantial part of his income on legal bills, and was even tried (and acquitted) for mail fraud.
Despite this, he was recognised for his pioneering work with the 1922 IEEE Medal of Honor, the 1923 Franklin Institute Elliott Cresson Medal and the 1946 American Institute of Electrical Engineers Edison Medal. *Wik





 2002 Claude Jacques Berge (5 June 1926 – 30 June 2002) was a French mathematician, recognized as one of the modern founders of combinatorics and graph theory.
Berge wrote five books, on game theory (1957), graph theory and its applications (1958), topological spaces (1959), principles of combinatorics (1968) and hypergraphs (1970), each being translated in several languages. These books helped bring the subjects of graph theory and combinatorics out of disrepute by highlighting the successful practical applications of the subjects. He is particularly remembered for two conjectures on perfect graphs that he made in the early 1960s but were not proved until significantly later:

A graph is perfect if and only if its complement is perfect, proven by László Lovász in 1972 and now known as the perfect graph theorem, and
A graph is perfect if and only if neither it nor its complement contains an induced cycle of odd length at least five, proven by Maria Chudnovsky, Neil Robertson, Paul Seymour, and Robin Thomas in work published in 2006 and now known as the strong perfect graph theorem.
Games were a passion of Claude Berge throughout his life, whether playing them – as in favorites such as chess, backgammon, and Hex – or exploring more theoretical aspects. This passion governed his interests in mathematics. He began writing on game theory as early as 1951, spent a year at the Institute for Advanced Study in Princeton, New Jersey in 1957, and the same year produced his first major book, Théorie générale des jeux à n personnes. Here, one not only comes across names such as John von Neumann and John Nash, as one would expect, but also names such as Dénes Kőnig, Øystein Ore, and Richardson. Indeed, the book contains much graph theory, namely the graph theory useful for game theory; it also contains much topology, namely the topology of relevance to game theory. Thus, it was natural that Berge quickly followed up on this work with two larger volumes, Théorie des graphes et ses applications and Espaces topologiques, fonctions multivoques. The first one is a masterpiece, with its unique blend of general theory, theorems – easy and difficult, proofs, examples, applications, diagrams. It is a personal manifesto of graph theory, rather than a complete description, as attempted in the book by Kőnig. It would be an interesting project to compare the first two earlier books on graph theory, by André Sainte-Laguë and Kőnig, respectively, with the book by Berge. It is clear that Berge's book is more leisurely and playful than Kőnig's, in particular. It is governed by the taste of Berge and might well be subtitled 'seduction into graph theory' (to use the words of Gian-Carlo Rota from the preface to the English translation of Berge's book). 

He is also known for his maximum theorem in optimization and for Berge's lemma, which states that a matching M in a graph G is maximum if and only if there is in G no augmenting path with respect to M. *wik





 2019 Mitchell Jay Feigenbaum (December 19, 1944 – June 30, 2019) was an American mathematical physicist whose pioneering studies in chaos theory led to the discovery of the Feigenbaum constants.

Feigenbaum was born in Philadelphia, Pennsylvania, to Jewish emigrants from Poland and Ukraine. He attended Samuel J. Tilden High School, in Brooklyn, New York, and the City College of New York. In 1964, he began his graduate studies at the Massachusetts Institute of Technology (MIT). Enrolling for graduate study in electrical engineering, he changed his area of study to physics. He completed his doctorate in 1970 for a thesis on dispersion relations, under the supervision of Professor Francis E. Low.

After short positions at Cornell University (1970–1972) and the Virginia Polytechnic Institute and State University (1972–1974), he was offered a longer-term post at the Los Alamos National Laboratory in New Mexico to study turbulence in fluids. He was at Cornell from 1982 to 1986 and then joined Rockefeller University as Toyota Professor in 1987. Although a complete theory of turbulent fluids remains elusive, Feigenbaum's research paved the way for chaos theory, providing groundbreaking insight into the many dynamical systems in which scientists and mathematicians find chaotic maps.

In 1983, he was awarded a MacArthur Fellowship, and in 1986, alongside Rockefeller University colleague Albert Libchaber, he was awarded the Wolf Prize in Physics "for his pioneering theoretical studies demonstrating the universal character of non-linear systems, which has made possible the systematic study of chaos". He was a member of the Board of Scientific Governors at the Scripps Research Institute. He remained at Rockefeller University as Toyota Professor from 1987 until his death.

Some mathematical mappings involving a single linear parameter exhibit the apparently random behavior known as chaos when the parameter lies within certain ranges. As the parameter is increased towards this region, the mapping undergoes bifurcations at precise values of the parameter. At first, one stable point occurs, then bifurcates to an oscillation between two values, then bifurcating again to oscillate between four values, and so on. Feigenbaum discovered in 1975, using an HP-65 calculator, that the ratio of the difference between the values at which such successive period-doubling bifurcations occur tends to a constant of around 4.6692... He was able to provide a mathematical argument of that fact, and he then showed that the same behavior, with the same mathematical constant, would occur within a wide class of mathematical functions, prior to the onset of chaos. The "ratio of convergence" measured in this study is now known as the first Feigenbaum constant.

The logistic map is a prominent example of the mappings that Feigenbaum studied in his noted 1978 article: "Quantitative Universality for a Class of Nonlinear Transformations".






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