## Friday, 22 September 2017

### On This Day in Math - September 22

Nothing is too wonderful to be true if it be consistent with the laws of nature.

~Michael Faraday in his Laboratory Notebook

The 265th day of the year; 265 is !6 (sub-factorial 6), the number of ways that six ordered objects can be mis-ordered so that each is in the wrong spot. See Subfactorial

The term "subfactorial "was introduced by Whitworth (1867 or 1878; Cajori 1993, p. 77). Euler (1809) calculated the first ten terms. For example, the only derangements of {1,2,3} are {2,3,1} and {3,1,2}, so !3=2

265 is the sum of two squares in two different ways, including one that is the sum of consecutive squares. $265 = 3^2 + 16^2 = 11^2 + 12^2$

2652 is also the sum of two squares in two different ways, making 265 the hypotenuse of two Pythagorean Triangles.

EVENTS

1602 In a public address at T¨ubingen University, Michael Mastlin, Kepler’s teacher, on the basis of chronological research put Jesus’ birth more than four years before the conventional date of A.D. 1. This date is now generally accepted. *VFR

1636 From a letter by Fermat to Roberval, it is clear that Fermat conceived the idea of analytic geometry as early as 1629, yet he published nothing on the subject. [Struik, Source Book, p. 397] *VFR

1792 This date is considered the beginning of the Republican Calendar of France, for on this date the Republic was proclaimed and this was also the date of the autumnal equinox in that year. The new calendar was not oﬃcially approved until 5 October 1793. *Cecil B. Read, “A book printed in the year VII,” The Mathematics Teacher, 59(1966), 138–140.

1822 “Jean-Francoise Champollion the younger wrote his famous Lettre a Monsieur Dacier, secr´etaire perp´etuel de l’Acad´ero¬emie royale des inscriptions et belles-lettres, relative a l’alphabet des hi´glyphes phon´etiques. On that day he opened the great book of Ancient Egypt, sealed for some two thousand years and now at last decipherable.” Quoted from p. 15 of Tutankhamen (1963) by Christiane Desroches-Noblecourt. *VFR

1986 In a decisive victory for the makers of a computer's insides, a federal judge ruled that code used to run computers and other electronic devices could be copyrighted like printed material.*CHM

2006 Britney Crystal Gallivan of Pomona, California was a keynote speaker at the September 22, 2006 National Council of Teachers of Mathematics convention. As a Junior in high school in 2002 she had disproved a commonly held mathematical myth that a piece of paper could not be folded more than eight times. Gallivan demonstrated that a single piece of toilet paper 4000 ft in length can be folded in half twelve times. Not only did she provide the empirical proof, but she also derived an equation that yielded the width of paper or length of paper necessary to fold a piece of paper of thickness t any n number of times. Wik

BIRTHS

1711 Thomas Wright (22 September 1711 – 25 February 1786) was an English astronomer, mathematician, instrument maker, architect and garden designer. He was the first to describe the shape of the Milky Way and speculate that faint nebulae were distant galaxies.
Wright is best known for his publication An original theory or new hypothesis of the Universe (1750), in which he explains the appearance of the Milky Way as "an optical effect due to our immersion in what locally approximates to a flat layer of stars."
Another of Thomas Wright's ideas, which is often attributed to Kant, was that many faint nebulae are actually incredibly distant galaxies.*Wik

1765 Paolo Ruffini born. He anticipated Abel by providing an almost correct proof of the insolubility of the quintic. *VFR Italian mathematician and physician who made studies of equations that anticipated the algebraic theory of groups. In 1799 Ruffini published a book on the theory of equations with his claim that quintics could not be solved by radicals, General theory of equations in which it is shown that the algebraic solution of the general equation of degree greater than four is impossible. Ruffini used group theory in his work but he had to invent the subject for himself. He also wrote on probability and the application of probability to evidence in court cases.*TIS (He also published the method now often called Horner's method ,,, see Horner below)

1769 Louis Puissant (22 Sept 1769, 10 Jan 1843) He is best remembered for his invention of a new map projection for a new map of France, and he was involved in the production of the map. The map was produced with considerable detail, the projection used spherical trigonometry, truncated power series and differential geometry. Puissant wrote on geodesy, the shape of the earth and spherical trigonometry. *SAU

1791 Michael Faraday born. (22 Sep 1791; 25 Aug 1867) English physicist and chemist whose many experiments contributed greatly to the understanding of electromagnetism. Although one of the greatest experimentalists, he was largely self-educated. Appointed by Sir Humphry Davy as his assistant at the Royal Institution, Faraday initially concentrated on analytical chemistry, and discovered benzene in 1825. His most important work was in electromagnetism, in which field he demonstrated electromagnetic rotation and discovered electromagnetic induction (the key to the development of the electric dynamo and motor). He also discovered diamagnetism and the laws of electrolysis. He published pioneering papers that led to the practical use of electricity, and he advocated the use of electric light in lighthouses. *TIS

DEATHS

1703 Vincento Viviani died. His problem of cutting four congruent windows in a hemispherical cupolo so that the remainder was quadrable led to Euler’s development of the double integral. *VFR The leading geometer of his time, who founded the Accademia del Cimento. As one of the first important scientific societies, this organization came before England's Royal Society. In 1639, at age 17, he became the student, secretary and assistant of Galileo (now blind) in Arcetri, until Galileo died in 1642. During his long career, Viviani published a number of books on mathematical and scientific subjects. He edited the first edition of Galileo's collected works (1655-1656), and worked tirelessly to have his master's memory rehabilitated. In 1660, together with Borelli, he measured the velocity of sound by timing the difference between the flash and the sound of a cannon. They obtained the value of 350 metres per second. *TIS

1837 William George Horner (1786 – 22 September 1837) was a British mathematician and schoolmaster. The invention of the zoetrope, in 1834 and under a different name (Daedaleum), has been attributed to him. *Wik
Horner is largely remembered only for the method, Horner's method, of solving algebraic equations ascribed to him by Augustus De Morgan and others. He published on the subject in the Philosophical Transactions of the Royal Society of London in 1819, submitting his article on 1 July. But Fuller has pointed out that, contrary to De Morgan's assertion, this article does not contain the method, although one published by Horner in 1830 does. Fuller has found that Theophilus Holdred, a London watchmaker, did publish the method in 1820 and comments"At first sight, Horner's plagiarism seems like direct theft. However, he was apparently of an eccentric and obsessive nature ... Such a man could easily first persuade himself that a rival method was not greatly different from his own, and then, by degrees, come to believe that he himself had invented it. "
This discussion is somewhat moot because the method was anticipated in 19th century Europe by Paolo Ruffini (What a strange coincidence that he dies on Ruffini's birthdate) , but had, in any case, been considered by Zhu Shijie in China in the thirteenth century. In the 19th and early 20th centuries, Horner's method had a prominent place in English and American textbooks on algebra. It is not unreasonable to ask why that should be. The answer lies simply with De Morgan who gave Horner's name and method wide coverage in many articles which he wrote.
Horner made other mathematical contributions, however, publishing a series of papers on transforming and solving algebraic equations, and he also applied similar techniques to functional equations. It is also worth noting that he gave a solution to what has come to be known as the "butterfly problem" which appeared in The Gentleman's Diary for 1815. The problem is the following:-
Let M be the midpoint of a chord PQ of a circle, through which two other chords AB and CD are drawn. Suppose AD cuts PQ at X and BC cuts PQ at Y. Prove that M is also the midpoint of XY.
The butterfly problem, whose name becomes clear on looking at the figure, has led to a wide range of interesting solutions. Finally we mention that Horner published Natural magic, a familiar exposition of a forgotten fact in optics (1832). *SAU

1922 Chen Ning Yang (22 Sep 1922, )Chinese-American theoretical physicist who shared the 1957 Nobel Prize for Physics (with Tsung-Dao Lee) for a ground-breaking theory that the weak force between elementary particles did not conserve parity, thus violating a previously accepted law of physics. (Parity holds that the laws of physics are the same in a right-handed system of coordinates as in a left-handed system.) The theory was subsequently confirmed experimentally by Chien-Shiung Wu in observations of beta decay. Yang is also known for his collaboration with Robert L. Mills. They developed the Yang-Mills fields theory - a mathematical idea for describing interactions among elementary particles and fields*TIS

1956 Frederick Soddy (2 Sep 1877, 22 Sep 1956). English chemist and physicist who received the Nobel Prize for Chemistry in 1921 for investigating radioactive substances. He suggested that different elements produced in different radioactive transformations were capable of occupying the same place on the Periodic Table, and on 18 Feb 1913 he named such species "isotopes" from Greek words meaning "same place." He is credited, along with others, with the discovery of the element protactinium in 1917 *TIS
Soddy is also the author of a mathematical poem about the solution to Descarte's four tangent circles theorem from the letter to Princess Elisabeth of Bohemia. The poem is called The Kiss Precise, and begins:
For pairs of lips to kiss maybe
Involves no trigonometry.
'Tis not so when four circles kiss
Each one the other three.
To bring this off the four must be
As three in one or one in three.
If one in three, beyond a doubt
Each gets three kisses from without.
If three in one, then is that one
Thrice kissed internally.

The complete poem and more about the history of the problem can be found here.

1970 Vojtěch Jarník (22 Dec 1897 , 22 Sept 1970) a Czech mathematician. His main area of work was in number theory and mathematical analysis; he proved a number of results on lattice point problems. He also developed the graph theory algorithm known as Prim's algorithm. The Vojtěch Jarník International Mathematical Competition, held each year in Ostrava, is named in his honor.*Wik

1979 Charles Ehresmann (19 April 1905, 22 Sept 1979) He was one of the creators of differential topology. Beginning in 1941, Ehresmann made major contributions toward establishing the current view of fibre spaces, manifolds, foliations and jets. His work in the creation and development of fibre spaces followed on from the study of a special case made earlier by Seifert and Whitney.
After 1957 Ehresmann became a leader in category theory and he worked in this area for 20 years. His principal achievements in this area concern local categories and structures defined by atlases, and germs of categories. The article [3] contains a list of 139 articles written by Ehresmann during his productive career as well as listing several volumes which he edited. *SAU

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, 21 September 2017

### On This Day in Math - September 21

To throw in a fair game at Hazards only three-spots, when something great is at stake, or some business is the hazard, is a natural occurrence and deserves to be so deemed; and even when they come up the same way for a second time if the throw be repeated. If the third and fourth plays are the same, surely there is occasion for suspicion on the part of a prudent man.
~Girolamo Cardano

The 264th day of the year; 264 = 23x3x11 is a harshad number (a number divisible by the sum of its digits). The word "Harshad" comes from the Sanskrit harṣa (joy) + da (give), meaning joy-giver. The numbers were defined and named by the famous Indian Mathematician D. R. Kaprekar.

Jim Wilder @wilderlab pointed out that the sum of all 2-digit numbers you can make from 264 totals 264... 24 + 42 + 26 + 62 + 46 + 64.

2642 = 69696, a palindrome; and 264 is the sum of ten consecutive primes.

Events
1781 Writing to his friend and mentor d’Alembert, Lagrange expressed concern that mathematics was reaching its creative end. “It seems,” he wrote, “that the mine is almost too deep already, and unless new seams are discovered, it will be necessary to abandon it sooner or later. Physics and chemistry now offer riches that are more brilliant and easier to exploit.” *Amir R. Alexander , Tragic Mathematics, Isis, Vol. 97, No. 4, December 2006

1784 The nation's first daily newspaper, the Pennsylvania Packet and Daily Advertiser, began publication on September 21, 1784. Many independent newspapers ran before that on a weekly or monthly basis. America's first independent newspaper, the New England Courant, was published by Benjamin Franklin's older brother in 1721. By the start of the Revolutionary War in 1775, there were 37 independent newspapers to keep the colonists informed. *Libray of Congress

1925 Edith Clarke patent for the Clark Calculator is approved. The calculator was a simple graphical device that solved equations involving electric current, voltage and impedance in power transmission lines. The device could solve line equations involving hyperbolic functions ten times faster than previous methods. She filed a patent for the calculator in 1921 and it was granted in 1925. Ms. Clarke is generally thought of as the first female electrical engineer in the U. S.

1984 Science reported (pp. 1379-1380) that Narendra Karmarkar of AT & T Bell Labs found a practical polynomial-time algorithm that is far faster than the simplex algorithm for linear programming problems. [Mathematics Magazine 58 (1985), p. 53]. *VFR

2012 Clear skies allowed a clear view of the fire balls which were witnessed right across the UK, Ireland and even parts of north west Europe.Bright 'meteor-like' tails could be seen in the sky for approximately two minutes at 10.55pm on Friday night.
The fireball was also seen in the US, "Portsmouth, RI, USA 2245 EST 4 to 5 seconds South to North Initially white, turned orange, then turned greenish-blue as it got low on horizon Like a flare but definately not a flare. Yes, from the "ball" itself. The tail was approximately 5 times longer than the ball itself. The tail remained a bright white even though the ball changed color. Was definitely not the typical "shooting star"."
According to the modeling done by Finnish mathematician Esko Lyytinen, the big UK fireball of the 21st of September was captured by Earths gravity.
After one circle around the Earth one of the remnants seems to have re-entered the skies over North America.
"It looks now that the fireball witnessed 155 minutes later in US and Canada, may have been one fragment of the British fireball, most probably the biggest one. This was its second entry into the Earths atmosphere", Lyytinen says. "If so, this is historical scientific observation, but it needs to be confirmed." * LunarMeteorite*Hunter and other sources

BIRTHS

1623 Stefano degli Angeli (21 Sept 1623 , 11 Oct 1697) His many mathematical works were on infinitesimals and he used them to study spirals, parabolas and hyperbolas. While in Venice he published De infinitorum parabolis (1654), De infinitorum spiralium spatiorum mensura (1660) which contains a generalisation of Archimedes' spiral, and De infinitorum cochlearum mensuris ac centris gravitatis (1661) which carries out Torricelli's intention of finding the centre of gravity of a solid body called a cochlea. The approach followed by Angeli in all these works is that of his teacher Cavalieri and of Torricelli, so when Guldin and Tacquet attacked these methods and defended the approach of the ancient Greeks, Angeli disputed with them over indivisibles. One has to see both sides in this argument for although Angeli's methods were much more powerful, they were less rigorous than the method of exhaustion adopted by Archimedes. Angeli examined fluid statics based on Archimedes' principle and Torricelli's experiments. He published Della gravita dell aria e fluidi in 1671 while holding the chair at Padua. He also considered the motion bodies falling towards a rotating Earth. Of course Angeli held the chair at Padua which had been held earlier by Galileo and his work shows strong influences from his predecessor. For example Angeli often refers to Galileo in his writings on physics, showing clearly how he has been influenced, particularly in terms of ways of approaching problems via the experimental method. Also clearly influenced by Galileo is Angeli's writings on the two systems of Ptolemy and Copernicus which he writes in Galileo's dialogue style.*SAU

1853 Heike Kamerlingh Onnes (21 Sep 1853; 21 Feb 1926) Dutch winner of the Nobel Prize for Physics in 1913 for his work on low-temperature physics and his production of liquid helium. He discovered superconductivity, the almost total lack of electrical resistance in certain materials when cooled to a temperature near absolute zero.*TIS

1884 Denes König (21 Sept 1884, 19 Oct 1944) His book, Theorie der endlichen und unendlichen Graphen, was published in 1936, and was a major factor in the growth of interest in graph theory worldwide. It was eventually translated into English under the title Theory of finite and infinite graphs (translated by R McCoart), Birkhauser, 1990; this also contains a biographical sketch by Tibor Gallai.
König's work on the factorisation of bipartite graphs relates closely to the marriage problem of Philip Hall. König's use of graphs to give a simpler proof of a determinant result of Frobenius seems to have led to some hostility between the two men.
After the Nazi occupation of Hungary, König worked to help persecuted mathematicians. This led to his death a few days after the Hungarian National Socialist Party took over the country. *SAU

1895 Joseph Leonard Walsh (21 Sept 1895, 6 Dec 1973) Walsh had a remarkable publication record. An obituary by Morris Marden (a student of Walsh) lists 279 articles, 7 books and 31 PhD students. He studied the relative location of the zeros of pairs of rational functions, zeros and topology of extremal polynomials, the critical points and level lines of Green's functions and other harmonic functions, conformal mappings, Padé approximation, and the interpolation and approximation of continuous, analytic or harmonic functions. Sewell writes "Polynomial approximation was neither discovered nor invented by J L Walsh (which may come as a surprise to some mathematicians). He is the one individual, however, who took a few scattered results on the subject and extended them, added mightily to them, and knit the whole together into a comprehensive, coherent theory." *SAU

1899 Juliusz Paweł Schauder (September 21, 1899, Lwów, Austria-Hungary – September 1943, Lwów, Occupied Poland) was a Polish mathematician of Jewish origin, known for his work in functional analysis, partial differential equations and mathematical physics.
He had to fight in World War I right after his graduation from school. He was captured and imprisoned in Italy. He entered the university in Lwów in 1919 and received his doctorate in 1923. He got no appointment at the university and continued his research while working as teacher at a secondary school. Due to his outstanding results, he obtained a scholarship in 1932 that allowed him to spend several years in Leipzig and, especially, Paris. In Paris he started a very successful collaboration with Jean Leray. Around 1935 Schauder obtained the position of a senior assistant in the University of Lwów.
Schauder was Jewish, and after the invasion of German troops in Lwów it was impossible for him to continue his work. In his letters to Swiss mathematicians, he wrote that he had important new results, but no paper to write them down. He was executed by the Gestapo, probably in October 1943.
Most of his mathematical work belongs to the field of functional analysis, being part of a large Polish group of mathematicians, i.e. Lwów School of Mathematics. They were pioneers in this area with wide applications in all parts of modern analysis. Schauder is best known for the Schauder fixed point theorem which is a major tool to prove the existence of solutions in various problems, the Schauder bases (a generalization of an orthonormal basis from Hilbert spaces to Banach spaces), and the Leray−Schauder principle, a way to establish solutions of partial differential equations from a priori estimates. *Wik

1907 Sir Edward Crisp Bullard (21 Sep 1907; 3 Apr 1980) English marine geophysicist noted for his work in geomagnetism who made the first satisfactory measurements of geothermal heat-flow through the oceanic crust. In early work, he measured minute gravitational variations by timing the swings of an invariant pendulum, which he used to study the East African Rift Valley. Bullard helped to develop the theory of continental drift. He made a computer analysis of the precise fit of the rifted continental borders along the two sides of the Atlantic Ocean, and presented his results to the Royal Society of London. He developed a "dynamo" theory of geomagnetism, which explained the Earth's magnetic field results from the convection of molten material within the Earth's core. He was knighted in 1953.*TIS

1926 Donald A. Glaser (21 Sep 1926, 28 Feb 2013)American physicist, who was awarded the Nobel Prize for Physics in 1960 for his invention of the bubble chamber in which the behavior of subatomic particles can be observed by the tracks they leave. A flash photograph records the particle's path. Glaser's chamber contains a superheated liquid maintained in a superheated, unstable state without boiling. A piston causing a rapid decrease in pressure creates a tendency to boil at the slightest disturbance in the liquid. Then any atomic particle passing through the chamber leaves a track of small gas bubbles caused by an instantaneous boiling along its path where the ions it creates act as bubble-development centers.*TIS  With the freedom that accompanies a Nobel Prize, he soon began to explore the new field of molecular biology, and in 1971 joined two friends, Ronald E. Cape and Peter Farley, to found the first biotechnology company, Cetus Corp., to exploit new discoveries for the benefit of medicine and agriculture. The company developed interleukin and interferon as cancer therapies, but was best known for producing a powerful genetic tool, the polymerase chain reaction, to amplify DNA. In 1991, Cetus was sold to Chiron Corp., now part of Novartis. Glaser died in his sleep Thursday morning, Feb. 28, at his home in Berkeley. He was 86. *Philosophy of Science Portal

DEATHS

1576 Girolamo Cardano (24 September 1501 – 21 September 1576)  He wrote more than 200 works on medicine, mathematics, physics, philosophy, religion, and music.His gambling led him to formulate elementary rules in probability, making him one of the founders of the field.
One story says that it was by his own hand so as to fulﬁll his earlier astrological prediction of of his death on this date. *H. Eves, Introduction to the History of Mathematics, Pg 221...
He was the first to give a clinical description of typhus fever. His book, Ars magna ("Great Art," 1545) was one of the great achievements in the history of algebra, in which he published the solutions to the cubic and quartic equations.(Ars Magna was the first Latin treatise devoted solely to algebra. In it he gave the methods of solution of the cubic and quartic equations which he had learned from Tartaglia.*SAU) His mechanical inventions included the combination lock, the compass gimbal consisting of three concentric rings, and the universal joint to transmit rotary motion at various angles (as used in present-day vehicles). He contributed to hydrodynamics and held that perpetual motion is impossible, except in celestial bodies. He published two encyclopedias of natural science and introduced the Cardan grille, a cryptographic tool (1550).*TIS

1842 Sir James Ivory (17 February 1765 – 21 September 1842) was a Scottish mathematician born in Dundee. He was essentially a self-trained mathematician, and was not only deeply versed in ancient and modern geometry, but also had a full knowledge of the analytical methods and discoveries of the continental mathematicians.
His earliest memoir, dealing with an analytical expression for the rectification of the ellipse, is published in the Transactions of the Royal Society of Edinburgh (1796); and this and his later papers on Cubic Equations (1799) and Kepler's Problem (1802) evince great facility in the handling of algebraic formulae. In 1804 after the dissolution of the flax-spinning company of which he was manager, he obtained one of the mathematical chairs in the Royal Military College at Marlow (afterwards removed to Sandhurst); and until the year 1816, when failing health obliged him to resign, he discharged his professional duties with remarkable success.*Wik

1859 Isidore Auguste Marie François Xavier Comte (28 January 1794 – 21 September 1859), better known as Auguste Comte (French: [oɡyst kɔ̃t]), was a French philosopher. He was a founder of the discipline of sociology and of the doctrine of positivism. He is sometimes regarded as the first philosopher of science in the modern sense of the term.
Strongly influenced by the utopian socialist Henri Saint-Simon, Comte developed the positive philosophy in an attempt to remedy the social malaise of the French Revolution, calling for a new social doctrine based on the sciences. Comte was a major influence on 19th-century thought, influencing the work of social thinkers such as Karl Marx, John Stuart Mill, and George Eliot.[3] His concept of sociologie and social evolutionism, though now outdated, set the tone for early social theorists and anthropologists such as Harriet Martineau and Herbert Spencer, evolving into modern academic sociology presented by Émile Durkheim as practical and objective social research.
Comte's social theories culminated in the "Religion of Humanity", which influenced the development of religious humanist and secular humanist organizations in the 19th century. Comte likewise coined the word altruisme (altruism)*Wik

1936 Frank Hornby (15 May 1863, 21 Sep 1936) English inventor and toy manufacturer who patented the Meccano construction set in 1901. This toy used perforated metal strips, wheels, roods, brackets, clips and assembly nuts and bolts to build unlimited numbers of models. His original sets, marketed as "Mechanics Made Easy" produced in a rented room, were initially sold at only one Liverpool toy shop. By 1908, he had formed his company, Meccano Ltd., and within five more years had established manufacturing in France, Germany, Spain and the U.S. He introduced Hornby model trains in 1920, originally clockwork and eventually electrically powered with tracks and scale replicas of associated buildings. The "Dinky" range of miniature cars and other motor vehicles was added in 1933. *TIS

1937 Chrystal Macmillan was the first female science graduate at Edinburgh University and the first female honours graduate in Mathematics. She went on to study at Berlin. She was the first woman to plead a case before the House of Lords. She became active in the Women's Suffrage Movement and went on to become a lawyer.*SAU

I'm not sure what, if any, were Milne's contributions to the war effort in WWII.
)

1981 Henry George Forder (27 Sept 1889, 21 Sept 1981) Forder spent much of his career in the Chair of Mathematics at Auckland. In fact he only once left New Zealand after settling there, this being in 1947 when he spent part of his leave in England. He spent 21 years building up the Mathematics Department at Auckland from a Department of a professor with one assistant when he arrived to one of six staff by the time he retired in 1955.
It is the books that Forder wrote which have given him a high reputation in the mathematical world. These are: The Foundations of Euclidean Geometry (1927), A School Geometry (1930), Higher Course Geometry (1931), The Calculus of Extension (1941), Geometry (1950), and Coordinates in Geometry (1953). In the Preface to the first of these, Forder writes, "Although the Euclidean geometry is the oldest of the sciences and has been studied critically for over two thousand years, it seems there is no textbook which gives a connected and rigorous account of that doctrine in the light of modern investigations. It is hoped that this book will fill the gap."
Geometry (1950) was reviewed by Donald Coxeter who was clearly fascinated by Forder's use of language, "The two-cusped epicycloid is described as the bright curve seen "when the sun shines on a cup of tea." ... The chapter on logical structure stresses the abstract nature of the order relation (ABC) by comparing it with the human relation "A prefers C to B." The possibility of coordinatising any descriptive geometry of three or more dimensions is epitomized in the statement that "we can create magnitudes from a mere muchness," and Archimedes' axiom in the statement that "you will always reach home, if you walk long enough." *SAU

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

## Wednesday, 20 September 2017

### On This Day in Math - September 20

Here I am: My brain is open.
[As an itinerant scholar, this was greeting he often gave, ready to collaborate, upon arrival at the home of any mathematician colleague.]
~ Paul Erdös

The 263rd day of the year; 263 is an irregular prime. (an odd prime which divides the numerator of a Bernoulli Number) They became of great interest after 1850 when Kummer proved that Fermat's Last Theorem was true for any exponent that was a regular prime.

$263^2 = 69169$ A strobogrammatic number (appears the same rotated by 180o.
Jim Wilder@wilderlab pointed out also that the length of 263!! is 263 digits.

263 is the sum of five consecutive primes, 263 = 43 + 47 + 53 + 59 + 61 , and the average of the primes on each side of it, $263 = \frac{257 + 269}{2}$

EVENTS
1623 Schickard writes to Kepler about Schickard's new calculating machine:
What you have done by calculation I have just tried to do by way of mechanics. I have conceived a machine consisting of eleven complete and six incomplete sprocket wheels; it calculates instantaneously and automatically from given numbers, as it adds, subtracts, multiplies and divides. You would enjoy seeing how the machine accumulates and transports spontaneously a ten or a hundred to the left and, vice-versa, how it does the opposite if it is subtracting ..."
Long before Pascal and Leibniz, Schickard invented a calculating machine, the 'Rechenuhr', in 1623 *SAU
.

1756 David Rittenhouse at age 24, wrote to Thomas Barton about his interest in optics during the French Indian War. “I have no health for a soldier,…I am so taken with optics that I do not know whether, if the enemy should invade this part of the country, as Archimedes was slain while making geometrical figures on the sand, so I should die making a telescope.” Barton was a minister and a graduate of Trinity College Dublin. They had met when Barton came to teach at Norriton in 1751. They developed a friendship and Barton loaned Rittenhouse books with which he learned Latin and Greek. Later, Barton would marry Rittenhouse’s Sister, Esther. *Harpers Monthly Magazine, vol LXIV 1882,

1786 Galvani made the crucial experiment on "animal electricity" when he proved that a dead and “prepared” frog jumped without an external electric source, just by touching muscles and nerves with a metallic arc. The frog functioned as a Leyden jar; it was an electric engine. Galvani made a breakthrough that was judged revolutionary by all the scientists of his time. *Walter Bernardi, The Controversy on Animal Electricity (paper on web)

1848 The American Association for the Advancement of Science met for the ﬁrst time, in Philadelphia. *VFR It was a reformation of the Association of American Geologists and Naturalists. The society chose William Charles Redfield as their first president because he had proposed the most comprehensive plans for the organization.*Wik

1916 The National Research Council met for the ﬁrst time, in New York. President Woodrow Wilson founded it for “encouraging the investigation of natural phenomena” for American business and national security. *VFR

1948 John von Neumann gave his ﬁrst lecture on the theory of automata. In this lecture, which was later published, he drew attention to the fundamental importance of the Universal Turing Machine. *A. Hodges, Alan Turing. The Enigma, p. 388

1954 Harlan Herrick of IBM runs the ﬁrst successful FORTRAN program. *VFR (Anyone know what it did?) FORTRAN, which is an acronym for "FORmula TRANslator," was invented at IBM by a group led by John Backus. FORTRAN's purpose was to simplify the programming process by allowing the programmer ("coder") to use simple algebra-like expressions when writing software. It also took over the task of keeping track of where instructions were kept in memory--a very laborious and error-prone procedure when undertaken by humans. FORTRAN is still in use today in scientific and engineering applications, making it one of the oldest programming languages still in use (COBOL is another). *CHM
The image shows members of the original Fortran team at a reunion at the National Computer Conference in 1982 *IBM Icons of Progress

1973 Skylab III Crew Encounters Strange Object In Orbit.  On the 59th day of flight Skylab III, the three-man crew saw and photographed a strange red object (see photos). Not more than 30-50 nautical miles from them, Alan Bean, Owen Garriott and Jack Lousman reported the object was brighter than any of the planets. First UFO in space?

BIRTHS

1842 Sir James Dewar (20 Sep 1842; 27 Mar 1923) British chemist and physicist. Blurring the line between physics and chemistry, he advanced the research frontier in several fields at the turn of the century, and gave dazzling lectures. His study of low-temperature phenomena entailed making an insulating double-walled flask of his own design by creating a vacuum between the two silvered layers of steel or glass (1892). This Dewar flask that has been named for him led to the domestic Thermos bottle. In June 1897, The Scientific American reported that "Dewar has just succeeded in liquefying fluorine gas at a temperature of -185 degrees C." He obtained liquid hydrogen in 1898. Dewar also invented cordite, the first smokeless powder.*TIS  In his book, Napoleon's Hemorrhoids, Phil Mason points out that Dewar never patented his vacuum flask.  His student, Reinhold Burger saw the commercial potential and began making the devices in Germany in 1904 under the patented name, thermos, Greek for heat.  Dewar was knighted, and Reinhold made millions.

1842 Alexander Wilhelm von Brill (20 Sept 1842, 8 June 1935) It is clear that Brill was much influenced by being a colleague of Klein's for five years and the influence would show up in many different ways throughout Brill's career. Brill taught a remarkably talented collection of students while at the Technische Hochschule in Munich including, for example Hurwitz, von Dyck, Rohn, Runge, Planck, Bianchi and Ricci-Curbastro. Although Klein left Munich in 1880, Brill was to remain there for a few more years, taking up the chair of mathematics in the University of Tübingen in 1884. Brill held this chair until he retired in 1918 at the age of 76, but continued to live and do mathematics in Tübingen after his retirement until his death at age 92.
He contributed to the study of algebraic geometry, trying to bring the rigour of algebra into the study of curves. In 1874 he published a joint work with Max Noether on properties of algebraic functions which are invariant under birational transformations. His work allowed the notion of genus of a curve, introduced by Clebsch, to be extended to singular and non-singular curves. In 1894 he wrote, again in collaboration with Max Noether, an extremely important survey of the development of the theory of algebraic functions.Brill also wrote on determinants, elliptic functions, special curves and surfaces. He wrote articles on the methodology of mathematics and on theoretical mechanics. At age 87 he wrote a book on Kepler's astronomy. *SAU

1887 Erich Hecke  (20 September 1887 – 13 February 1947) was a German mathematician. He obtained his doctorate in Göttingen under the supervision of David Hilbert. Kurt Reidemeister and Heinrich Behnke were among his students.
Hecke was born in Buk, Posen, Germany (now Poznań, Poland), and died in Copenhagen, Denmark. His early work included establishing the functional equation for the Dedekind zeta function, with a proof based on theta functions. The method extended to the L-functions associated to a class of characters now known as Hecke characters or idele class characters: such L-functions are now known as Hecke L-functions. He devoted most of his research to the theory of modular forms, creating the general theory of cusp forms (holomorphic, for GL(2)), as it is now understood in the classical setting.*Wik

1915 Joseph Waksberg, (20 September 1915, 10 January 2006) born in Kielce, Poland, came to the United States with his family in 1921. He joined the Census Bureau in 1940, remaining there for 33 years. He then joined the stat-research firm Westat, becoming Chairman of the Board in 1990, taking over for Morris Hansen. Also, from 1967 to 1997, he served as a consultant to CBS and other TV networks for Election Night analysis.
Mr. Waksberg's 1978 paper in JASA, "Sampling Methods for Random Digit Dialing", resulted in the Mitofsky-Waksberg Method of RDD. [For a description of the Method, see the Sept 17th posting for Warren Mitofsky.] Generally, Warren Mitofsky developed the Method intuitively and Waksberg, on Mitofsky's request, developed it mathematically, resulting in his 1978 paper. *David Bee

DEATHS

1804 Pierre (-François-André) Méchain (16 Aug 1744, 20 Sep 1804) was a French astronomer and hydrographer at the naval map archives in Paris recruited by Jean Delambre. He was a mathematical prodigy. In 1790, they were chosen by the National Assembly to establish a decimal system of measurement based on the meter. Since this was defined to be one ten-millionth of the distance between the Earth's pole and the equator, Mechain led a survey of the meridian arc from Dunkirk, France, to Barcelona, Spain. Through his astronomical observations, Mechain discovered 11 comets and provided 26 additions to Messier's catalog. He calculated the orbits of the two comets he found in 1781. Mechain died of yellow fever while making further surveys for the meridian measurement. *TIS

1873 Giovanni Battista Donati (16 Dec 1826, 20 Sep 1873) Italian astronomer who, on 5 Aug 1864, was first to observe the spectrum of a comet (Tempel 1864 II), showing not merely reflected sunlight but also spectral lines from luminous gas forming the comet tail when near the Sun. Earlier, he discovered the comet known as Donati's Comet at Florence, on 2 Jun 1858. When the comet was nearest the earth, its triple tail had an apparent length of 50°, more than half the distance from the horizon to the zenith and corresponding to the enormous linear figure of more than 72 million km (about 45 million mi). With an orbital period estimated at more than 2000 years, it will not return until about the year 4000.*TIS This comet is often called the 2nd most brilliant of the 19th Century.

1878 George Parker Bidder (13 June 1806 – 20 September 1878) was an English engineer and calculating prodigy. Born in the town of Moretonhampstead, Devon, England, he displayed a natural skill at calculation from an early age. In childhood, his father, William Bidder, a stonemason, exhibited him as a "calculating boy", first in local fairs up to the age of six, and later around the country. In this way his talent was turned to profitable account, but his general education was in danger of being completely neglected.
Still many of those who saw him developed an interest in his education, a notable example being Sir John Herschel. His interest led him to arrange it so George could be sent to school in Camberwell. There he did not remain long, being removed by his father, who wished to exhibit him again, but he was saved from this misfortune and enabled to attend classes at the University of Edinburgh, largely through the kindness of Sir Henry Jardine,
On leaving college in 1824 he received a post in the ordnance survey, but gradually drifted into engineering work.
Bidder died at Dartmouth, Devon and was buried at Stoke Fleming.
His son, George Parker Bidder, Jr. (1836–1896), who inherited much of his father's calculating power, was a successful parliamentary counsel and an authority on cryptography. His grandson, also named George Parker Bidder, became a marine biologist and president of the Marine Biological Association of the United Kingdom from 1939 to 1945. *Wik

1882 Charles Auguste Briot (19 July 1817,  20 Sept 1882) undertook research on analysis, heat, light and electricity. His first major work on analysis was Recherches sur la théorie des fonctions which he published in the Journal of the École Polytechnique in 1859, and he also published this work as a treatise in the same year. His researches on heat, light and electricity was all based on his theories of the aether. He was strongly influenced in developing these theories by Louis Pasteur, the famous chemist. Of course Pasteur was a great scientist, but Briot had an additional reason to hold him in high esteem for, like himself and his friend Bouquet, Pasteur was brought up in the Doubs region of France.
In 1859 Briot and Bouquet published their important two volume treatise on doubly periodic functions. They published another joint effort in 1875 when their treatise on elliptic functions appeared. In this same year they published a second edition to their two volume work of 1859. In 1879 Briot, this time in a single author work, produced his treatise on abelian functions. The physical motivation for the mathematical theories which gave rise to this work in analysis was published by Briot in 1864 when he published his work on light, Essai sur la théorie mathématique de la lumière and five years later when he published his work on heat, Théorie mécanique de la chaleur.
We noted above that Briot was a dedicated teacher and as such he wrote a great number of textbooks for his students. This was certainly a tradition in France at this time and it was natural for a teacher of Briot's quality to write up his courses as textbooks. He wrote textbooks which covered most of the topics from a mathematics course: arithmetic, algebra, calculus, geometry, analytic geometry, and mechanics. For his outstanding contributions to mathematics the Académie des Sciences in Paris awarded Briot their Poncelet Prize in 1882 shortly before he died. *SAU

1930 Moritz Pasch (8 Nov 1843, 20 Sept 1930) was a German mathematician who worked on the foundations of geometry. He found a number of assumptions in Euclid that nobody had noticed before. "Pasch's analysis relating to the order of points on a line and in the plane is both striking and pertinent to its understanding. Every student can draw diagrams and see that if a point B is between A and a point C, then C is not between A and B, or that every line divides a plane into two parts. But no one before Pasch had laid a basis for dealing logically with such observations. These matters may have been considered too obvious; but the result of such neglect is the need to refer constantly to intuition, so that the logical status of what is being done cannot become clear." *SAU

1939 Karl Hermann Brunn (August 1, 1862 – September 20, 1939) was a German mathematician, known for his work in convex geometry and in knot theory. He is recognized with the Brunn–Minkowski inequality and in Brunnian links in knot theory. A Brunnian link is a nontrivial link that becomes trivial if any component is removed. In other words, cutting any loop frees all the other loops (so that no two loops can be directly linked).
1982 Frederick Bath graduated from Bristol and Cambridge and held posts at King's College London, University College Dundee, St Andrews and Edinburgh. He worked in Geometry. He was president of the EMS in 1938 and 1939. *SAU

1996 Paul Erdös ( 26 Mar 1913, 20 Sep 1996) Hungarian mathematician, who was one of the century's top math experts and pioneered the fields of number theory and combinatorics. The type of mathematics he worked on were beautiful problems that were simple to understand, but notoriously difficult to solve. At age 20, he discovered a proof for a classic theorem of number theory that states that there is always at least one prime number between any positive integer and its double. In the 1930s, he studied in England and moved to the USA by the late 1930s when his Jewish origins made a return to Hungary impossible. Affected by McCarthyism in the 1950s, he spent much of the next ten years in Israel. Writing his many hundreds of papers made him one of history's most prolific mathematicians. *TIS (I learned of his death after some students in my Pre-calc class told me on the 21st. He was one of my favorites and I had been talking about him just days before. They had seen it on the morning news)

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 M = Women of Mathematics, Grinstein & Campbell

## Tuesday, 19 September 2017

### On This Day in Math - September 19

Mankind will not remain on the earth forever, but, in search of light and space, will at first timidly penetrate beyond the limits of the atmosphere and then finally conquer the spaces of the solar system.
— Konstantin Eduardovich Tsiolkovsky
tombstone inscription

The 262nd day of the year; 262 is the 5th meandric number. A meander is a self-avoiding closed curve which intersects a line a number of times. Intuitively, a meander can be viewed as a straight road crossing a river over a number of bridges.[ The term meander is drawn from the Greek name of an actual winding river, the Maiandros.]

262 is the number of equilateral triangles formed out of matches in a hexagonal chunk with four matchsticks on a side..(Can you find the 38 equilaterals in the hexagon with two matchsticks on a side)

EVENTS

1648 The theory of atmospheric pressure and the existence of a vacuum were conﬁrmed by experiments designed by Blaise Pascal.*VFR

1680 Francis and Mary Huntrodds die within five hours on their mutual birthday, and marriage anniversary. Statisticians sometimes hold "probability" parties in honor of Huntrodd's Day. *David Spiegelhalter, understandinguncertainty.org

1783 The brothers Montgolﬁer repeated their experiment of 4 June 1783, in the presence of Louis XVI at Versailles. At one o’clock the crowd went wild as the balloon soared gracefully free carrying a rooster, a sheep, and a duck.*VFR

In 1848, Hyperion, moon of Saturn, discovered by William Cranch Bond(US), George Phillips Bond(US) and William Lassell(UK)*TIS  It was the first non-round moon to be discovered. Hyperion's discovery came shortly after John Herschel had suggested names for the seven previously-known satellites of Saturn in his 1847 publication Results of Astronomical Observations made at the Cape of Good Hope. Lassell, who saw Hyperion two days after William Bond, had already endorsed Herschel's naming scheme and suggested the name Hyperion in accordance with it. He also beat Bond to publication. *Wik

1861 Russian chemist Alexander Butlerov first presented a definition for "chemical structure".
Chemical structure refers to the way atoms are arranged within molecules. Butlerov realised that chemical compounds are not a random cluster of atoms and functional groups, but structures with definite order. *.rsc.org

1894 In a letter to Felix Klein (19 September 1894) Peano wrote: “The purpose of mathematical logic is to analyze the ideas and reasoning that especially figure in the mathematical sciences.” Peano was neither a logicist nor a formalist. He believed rather that mathematical ideas are ultimately derived from our experience of the material world. *Hubert Kennedy, "Eight Mathematical Biographies" Pg 27

1994   Andrew Wiles has an "AHA" moment,    Over the course of three lectures delivered at Isaac Newton Institute for Mathematical Sciences on June 21, 22, and 23 of 1993, Wiles had announced his proof of the Taniyama–Shimura conjecture, and hence of Fermat's Last Theorem. There was a relatively large amount of press coverage afterwards.
After announcing his results, (Nick) Katz was a referee on his manuscript and he asked Wiles a series of questions that led Wiles to recognize that the proof contained a gap. There was an error in a critical portion of the proof which gave a bound for the order of a particular group: the Euler system used to extend Flach's method was incomplete. Wiles and his former student Richard Taylor spent almost a year resolving it. Wiles indicates that on the morning of September 19, 1994 he realized that the specific reason why the Flach approach would not work directly suggested a new approach with the Iwasawa theory which resolved all of the previous issues with the latter and resulted in a CNF that was valid for all of the required cases. On 6 October Wiles sent the new proof to three colleagues including Faltings. The new proof was published and, despite its size, widely accepted as likely correct in its major components. *Wik

1995 Ahoy Matey,  International "Talk Like a Pirate Day is born"  is a parodic holiday created in 1995 by John Baur (Ol' Chumbucket) and Mark Summers (Cap'n Slappy), of Albany, Oregon, who proclaimed September 19th each year as the day when everyone in the world should talk like a pirate.For example, an observer of this holiday  would greet friends not with "Hello," but with "Ahoy, matey!" The  holiday, and its observance, springs from a romanticized view of the Golden Age of Piracy. *Wik

2009  at the autumn meeting of the British Society for the History of Mathematics (BSHM), The Archimedes Codex by Reviel Netz and William Noel was awarded the Neumann Prize for the best book in the history of mathematics aimed a broad audience. Reviel Netz is Professor of Classics at Stanford University, California, and Dr William Noel is the curator of manuscripts and rare books at The Walters Art Museum in Baltimore, Maryland.
The prize was awarded for the first time this year and will henceforth be bestowed every two years. The prize is named after Dr Peter Neumann, Emeritus Fellow of The Queen’s College, Oxford, and a former president of the BSHM. He was awarded the OBE in 2008 for his services to education.
The Archimedes Codex is a biography of one of the ancient world’s greatest mathematicians Archimedes of Syracuse (c.287 BC – c.212 BC) and tells the story of the rediscovery of a 10th-century copy of some of his writings and drawings, which were found hidden beneath a 13th-century prayer book. *History Today, September 23, 2009

BIRTHS

1749 Jean-Baptiste Joseph Delambre (19 Sep 1749; 18 Aug 1822)  He conducted a geodetic survey be-tween Dunkerque and Rodez which was instrumental in establishing the length of the meter. *VFR

1840 John Emory McClintock (19 Sept 1840 , 10 July 1916) for many years the leading actuary in America. He published 30 papers between 1868 and 1877 on actuarial questions. His publications were not confined to questions relating to life insurance policies however. He published about 22 papers on mathematical topics. One paper treats difference equations as differential equations of infinite order and others look at quintic equations which are soluble algebraically. He published A simplified solution of the cubic in 1900 in the Annals of Mathematics. Another work, On the nature and use of the functions employed in the recognition of quadratic residues (1902), published in the Transactions of the American Mathematical Society, is on quadratic residues.*SAU

1888 James Waddell Alexander (19 Sep 1888; 23 Sept 1971) American mathematician and a founder of the branch of mathematics originally known as analysis situs, now called topology. In 1912, he joined the faculty of the mathematics department at Princeton. Soon after, Alexander generalised the Jordan curve theorem and, in 1928, he discovered the Alexander polynomial which is much used in knot theory.*TIS

1908 Victor Frederick Weisskopf (September 19, 1908 – April 22, 2002) was an Austrian-born American theoretical physicist. He did postdoctoral work with Werner Heisenberg, Erwin Schrödinger, Wolfgang Pauli and Niels Bohr.[1] During World War II he worked at Los Alamos on the Manhattan Project to develop the atomic bomb, and later campaigned against the proliferation of nuclear weapons.
His brilliance in physics led to work with the great physicists exploring the atom, especially Niels Bohr, who mentored Weisskopf at his institute in Copenhagen. By the late 1930s, he realized that, as a Jew, he needed to get out of Europe. Bohr helped him find a position in the U.S.
In the 1930s and 1940s, 'Viki', as everyone called him, made major contributions to the development of quantum theory, especially in the area of Quantum Electrodynamics.[3] One of his few regrets was that his insecurity about his mathematical abilities may have cost him a Nobel prize when he did not publish results (which turned out to be correct) about what is now known as the Lamb shift. *Wik

1964  Simon Singh (19 September, 1964 - )In 1950 my parents emigrated to Taunton. A few years later they moved to Wellington, and that is where I was born. Somerset is a fertile ground for budding scientists. Just 5 miles from where I was born is the town of Milverton, the birthplace of Thomas Young, the polymath who made breakthroughs in a wide range of subjects. Most important of all, he advocated the wave theory of light. He studied at Emmanuel College Cambridge, and in due I course I attended the same college, but I failed to make any significant contributions to the foundations of physics.
Before starting my physics degree at Imperial College, London, I spent a year at GEC Hirst Research Centre, Wembley, working on gallium arsenide monolithic microwave integrated circuits. GEC were sponsoring me during my studies. It was an interesting year and I grew up a bit, but the main lesson I learned was that my future did not rest in industrial research and development.
My PhD in experimental particle physics was based at Cambridge University, but I spent most of my three years working at the European Centre for Particle Physics (CERN) in Geneva. I worked as part of the UA2 collaboration, which had previously won the Nobel Prize for discovering the W and Z bosons. It was a wonderful three years.
Particle physics was great fun. My three years at Cambridge and CERN were challenging and stimulating. However, I could see that there were people around me who were on a different planet when it came to understanding and researching physics, and it would be they who would go on to make their names as pioneers. As for me, it was time to change career. I had always enjoyed talking about and explaining science, so I took the decision to move towards a career in journalism and science communication. In particular, I have always loved television and felt that this was the most influential medium, so I started applying for a job at the BBC.  *From his personal biography on his web page.
Simon Singh is the author of numerous popular science books, including the one below:

DEATHS

1710 Olaus Roemer, (25 Sep 1644 - 19 Sep 1710) Danish astronomer,  He was the ﬁrst to measure the speed of light. *VFR  Astronomer who demonstrated conclusively that light travels at a finite speed. He measured the speed by precisely measuring the length of time between eclipses of Jupiter by one of its moons. This observation produces different results depending on the position of the earth in its orbit around the sun. He reasoned that meant light took longer to travel the greater distance when earth was traveling in its orbit away from Jupiter.*TIS

1761 Pieter van Musschenbroek (14 Mar 1692; 19 Sep 1761 at age 69) Dutch mathematician and physicist who invented the Leyden jar, the first effective device for storing static electricity. He grew up in a family that manufactured scientific instruments such as telescopes, microscopes and air pumps. Before Musschenbroek's invention, static electricity had been produced by Guericke using a sulphur ball, with minor effects. In Jan 1746, Musschenbroek placed water in a metal container suspended on silk cords, and led a brass wire through a cork into the water. He built up a charge in the water. When an unwary assistant touched the metal container and the brass wire, the discharge from this apparatus delivered a substantial shock of static electricity. The Leyden name is linked to the discovery having being made at the University of Leiden. *TIS

1843 Gaspard Gustave de Coriolis (21 May 1792, 19 Sept 1843) Coriolis is best remembered for the Coriolis force. He showed that the laws of motion could be used in a rotating frame of reference if an extra force called the Coriolis acceleration is added to the equations of motion. *SAU

1935 Konstantin Eduardovich Tsiolkovsky (17 Sep 1857, 19 Sep 1935) Russian pioneer space theorist who, while a provincial Russian schoolteacher, worked out many of the principles of space travel. In 1883, he noted that vehicle in space would travel in the opposite direction to gas that it emitted, and was the first to seriously propose this method propulsion in space travel. He wrote various papers, including the 1903 article "Exploration of Space with Reactive Devices."  The engineering equations he derived included parameters such as specific impulse, thrust coefficient and area ratio. He established that the most efficient chemical combination would be that of liquid hydrogen and liquid oxygen. He was later recognized by the Soviet Union as the "father of cosmonautics." He also built the first wind tunnel.*TIS  (He is buried at the Park of the Cosmonauts' Museum, Kaluga Province, Russian Federation)

1968 Chester Floyd Carlson (8 Feb 1906, 19 Sep 1968) American physicist who invented xerography (22 Oct 1938), an electrostatic dry-copying process that found applications ranging from office copying to reproducing out-of-print books. The process involved sensitizing a photoconductive surface to light by giving it an electrostatic charge Carlson developed it between 1934 and 1938, and initially described it as electrophotography It was immediately protected by Carlson with an impenetrable web of patents, though it was not until 1944 that he was able to obtain funding for further development. In 1947 he sold the commercial rights for his invention to the Haloid Company, a small manufacturer of photographic paper (which later became the Xerox Corporation).*TIS

2010 Joseph Bernard Kruskal, Jr. (January 29, 1928 – September 19, 2010) was an American mathematician, statistician, computer scientist and psychometrician. He was a student at the University of Chicago and at Princeton University, where he completed his Ph.D. in 1954, nominally under Albert W. Tucker and Roger Lyndon, but de facto under Paul Erdős with whom he had two very short conversations.Kruskal has worked on well-quasi-orderings and multidimensional scaling.
He was a Fellow of the American Statistical Association, former president of the Psychometric Society, and former president of the Classification Society of North America.
In statistics, Kruskal's most influential work is his seminal contribution to the formulation of multidimensional scaling. In computer science, his best known work is Kruskal's algorithm for computing the minimal spanning tree (MST) of a weighted graph. In combinatorics, he is known for Kruskal's tree theorem (1960), which is also interesting from a mathematical logic perspective since it can only be proved nonconstructively. Kruskal also applied his work in linguistics, in an experimental lexicostatistical study of Indo-European languages, together with the linguists Isidore Dyen and Paul Black.
Kruskal was born in New York City to a successful fur wholesaler, Joseph B. Kruskal, Sr. His mother, Lillian Rose Vorhaus Kruskal Oppenheimer, became a noted promoter of Origami during the early era of television.  He died in Princeton. *Wik

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

## Monday, 18 September 2017

### On This Day in Math - September 18

Lisez Euler, lisez Euler, c'est notre maître à tous.

—~Pierre-Simon Laplace

The 261st day of the year; 261 is the number of possible unfolded tesseract patterns. (I  just learned recently that Charles Howard Hinton coined the term tesseract  (4-dimensional "cube").  He is also the inventor of the baseball  pitching gun.) (see Baseball and the Fourth Dimension)

If you draw diagonals in a 16 sided polygon, it is possible to dissect it into 7 quadrilaterals.  There are 261 unique  ways to  make this dissection.

EVENTS

1820 André Marie AMPÈRE describes electromagnetic effect.  On 11 September 1820 he heard of H. C. Ørsted's discovery that a magnetic needle is acted on by a voltaic current. Only a week later, on 18 September, Ampère presented a paper to the Academy containing a much more complete exposition of that and kindred phenomena. On the same day, Ampère also demonstrated before the Academy that parallel wires carrying currents attract or repel each other, depending on whether currents are in the same (attraction) or in opposite directions (repulsion). This laid the foundation of electrodynamics.*Wik.

In 1830, B&O locomotive Tom Thumb, the first locomotive built in America, lost in a 14-km race with a horse due to a boiler leak.*TIS

1846  Le Verrier transmits his most famous achievement, his prediction of the existence of the then unknown planet Neptune, using only mathematics and astronomical observations of the known planet Uranus. Encouraged by physicist Arago Director of the Paris Observatory, Le Verrier was intensely engaged for months in complex calculations to explain small but systematic discrepancies between Uranus's observed orbit and the one predicted from the laws of gravity of Newton. At the same time, but unknown to Le Verrier, similar calculations were made by John Couch Adams in England. Le Verrier announced his final predicted position for Uranus's unseen perturbing planet publicly to the French Academy on 31 August 1846, two days before Adams's final solution, which turned out to be 12° off the mark, was privately mailed to the Royal Greenwich Observatory. Le Verrier transmitted his own prediction by 18 September letter to Johann Galle of the Berlin Observatory. The letter arrived five days later, and the planet was found with the Berlin Fraunhofer refractor that same evening, 23 September 1846, by Galle and Heinrich d'Arrest within 1° of the predicted location near the boundary between Capricorn and Aquarius.*Wik

1948 Alan Turing writes to Jack Good and mentions, "Chess machine designed by Champ and myself..". *Turing Archive

BIRTHS

1752 Adrien-Marie Legendre (18 Sep 1752; 10 Jan 1833) French mathematician who contributed to number theory, celestial mechanics and elliptic functions. In 1794, he was put in charge of the French government's department that was standardizing French weights and measures. In 1813, he took over as head of the Bureau des Longitudes upon the death of Lagrange, its former chief. It was in a paper on celestial mechanics concerning the motion of planets (1784) that he first introduced the Legendre Polynomials. His provided outstanding work on elliptic functions (1786), and his classic treatise on the theory of numbers (1798) and also worked on the method of least squares. *TIS

1819 Jean Bernard Léon Foucault (18 Sep 1819; 11 Feb 1868) French physicist whose Foucault Pendulum experimentally proved that the Earth rotates on its axis (6 Jan 1851). Using a long pendulum with a heavy bob, he showed its plane rotated at a rate related to Earth's angular velocity and the latitude of the site. He studied medicine and physics and became an assistant at the Paris Observatory (1855). He invented an accurate test of a lens for chromatic and spherical aberations. Working with Fizeau, and also independently, he made accurate measurements of the absolute velocity of light. In 1850, Foucault showed that light travels slower in water than in air. He also built a gyroscope (1852), the Foucault's prism (1857) and made improvements for mirrors of reflecting telescopes. *TIS (a brief biography of Foucault is here)

1839 John Aitken (18 Sep 1839; 14 Nov 1919) Scottish physicist and meteorologist who, through a series of experiments and observations in which he used apparatus of his own design, elucidated the crucial role that microscopic particles, now called Aitken nuclei, play in the condensation of atmospheric water vapour in clouds and fogs. Ill health prevented Aitken from holding any official position; he worked instead in the laboratory in his home in Falkirk. Much of his work was published in the journals of the Royal Society of Edinburgh, of which he was a member.*TIS

1854 Sir Richard Tetley Glazebrookb(18 Sep 1854; 15 Dec 1935) English physicist who was the first director of the UK National Physical Laboratory, from 1 Jan 1900 until his retirement in Sep 1919. At first, the laboratory's income depended on much routine, commercial testing, but Glazebrook championed fundamental, industrially oriented research. With support from individual donors, buildings were added for electrical work, metrology, and engineering. Data useful to the shipbuilding industry was collected in pioneering experimental work on models of ships made possible by a tank funded by Alfred Yarrow (1908). From 1909, laboratory began work benefitting the embryonic aeronautics industry, at the request of the secretary of state for war. The lab to contributed substantially to military needs during WW I *TIS

1907 Edwin Mattison McMillan (Sep 18, 1907 - September 7, 1991) McMillan was an American physicist and Nobel laureate credited with being the first-ever to produce a transuranium element, neptunium. For this, he shared the Nobel Prize in Chemistry with Glenn Seaborg in 1951.
McMillan and his colleagues discovered the elements neptunium (Np) and plutonium (Pu), the two elements following uranium (U) in the periodic table. Their names were inspired by the position of the planets in the solar system - Neptune is beyond Uranus and Pluto (before being declassified as a planet) is beyond Neptune. *http://www.rsc.org/

1863 William Henry Metzler (18 Sept 1863, 18 April 1943) was a Canadian mathematician who graduated from Toronto University and taught at Syracuse University and Albany Teachers Training College, both in New York State. He published papers on the theory of matrices and determinants, several of them in the Proceedings of the EMS. *SAU

1926 James Cooley, (September 18, 1926 - ) co-creator of the fast Fourier transform, was born. Working with John Tukey, Cooley in 1965 worked out a vast improvement to a common mathematical algorithm called the Fourier transform. Although the algorithm had been useful in computing, its complexity required too much time. While working at IBM, Cooley built on Tukey's ideas for a swifter version. *CHM

DEATHS

1783 Leonhard Euler dies (15 Apr 1707, 18 Sep 1783) . After having discussed the topics of the day, the Montgolﬁers, and the discovery of Uranus, “He [Euler] ceased to calculate and to live,”according to the oft-quoted words of de Condorcet. *VFR   Swiss mathematician and physicist, one of the founders of pure mathematics. He not only made decisive and formative contributions to the subjects of geometry, calculus, mechanics, and number theory but also developed methods for solving problems in observational astronomy and demonstrated useful applications of mathematics in technology. At age 28, he blinded one eye by staring at the sun while working to invent a new way of measuring time. *TIS (Students who have not, should read Dunham's "Euler, The Master of us All")

1891 William Ferrel (born 29 Jan 1817, 18 Sep 1891) American meteorologist was an important contributor to the understanding of oceanic and atmospheric circulation. He was able to show the interrelation of the various forces upon the Earth 's surface, such as gravity, rotation and friction. Ferrel was first to mathematically demonstrate the influence of the Earth's rotation on the presence of high and low pressure belts encircling the Earth, and on the deflection of air and water currents. The latter was a derivative of the effect theorized by Gustave de Coriolis in 1835, and became known as Ferrel's law. Ferrel also considered the effect that the gravitational pull of the Sun and Moon might have on the Earth's rotation and concluded (without proof, but correctly) that the Earth's axis wobbles a bit. *TIS (A more complete biography is here)

1896 Armand Hippolyte Fizeau (23 Sep 1819, 18 Sep 1896) French physicist was the first to measure the speed of light successfully without using astronomical calculations (1849). Fizeau sent a narrow beam of light between gear teeth on the edge of a rotating wheel. The beam then traveled to a mirror 8 km/5 mi away and returned to the wheel where, if the spin were fast enough, a tooth would block the light. Knowing this time from the rotational speed of the wheel, and the mirror's distance, Fizeau directly measured the speed of light. He also found that light travels faster in air than in water, which confirmed the wave theory of light, and that the motion of a star affects the position of the lines in its spectrum. With Jean Foucault, he proved the wave nature of  the Sun's heat rays by showing their interference (1847). *TIS

1913 Samuel Roberts FRS (15 December 1827, Horncastle, Lincolnshire – 18 September 1913, London) was a British mathematician.
Roberts studied at Queen Elizabeth's Grammar School, Horncastle. He matriculated in 1845 at the University of London, where he earned in 1847 his bachelor's degree in mathematics and in 1849 his master's degree in mathematics and physics, as first in his class. Next he studied law and became a solicitor in 1853. After a few years of law practice he abandoned his law career and returned to mathematics, although he never had an academic position. He had his first mathematical paper published in 1848. In 1865 he was an important participant in the founding of the London Mathematical Society (LMS). From 1866 to 1892 he acted as legal counsel for LMS, from 1872 to 1880 he was the organization's treasurer, and from 1880 to 1882 its president. In 1896 he received the De Morgan Medal of the LMS. In 1878 he was elected FRS.
Roberts published papers in several fields of mathematics, including geometry, interpolation theory, and Diophantine equations.
Roberts and Pafnuty Chebyschev are jointly credited with the Roberts-Chebyshev theorem related to four-bar linkages *Wik

1967 Sir John Douglas Cockcroft (27 May 1897, 18 Sep 1967) British physicist, who shared (with Ernest T.S. Walton of Ireland) the 1951 Nobel Prize for Physics for pioneering the use of particle accelerators to study the atomic nucleus. Together, in 1929, they built an accelerator, the Cockcroft-Walton generator, that generated large numbers of particles at lower energies - the first atom-smasher. In 1932, they used it to disintegrate lithium atoms by bombarding them with protons, the first artificial nuclear reaction not utilizing radioactive substances. They conducted further research on the splitting of other atoms and established the importance of accelerators as a tool for nuclear research. Their accelerator design became one of the most useful in the world's laboratories. *TIS

1977 Paul Isaak Bernays (17 Oct 1888, 18 Sep 1977) Swiss mathematician and logician who is known for his attempts to develop a unified theory of mathematics. Bernays, influenced by Hilbert's thinking, believed that the whole structure of mathematics could be unified as a single coherent entity. In order to start this process it was necessary to devise a set of axioms on which such a complete theory could be based. He therefore attempted to put set theory on an axiomatic basis to avoid the paradoxes. Between 1937 and 1954 Bernays wrote a whole series of articles in the Journal of Symbolic Logic which attempted to achieve this goal. In 1958 Bernays published Axiomatic Set Theory in which he combined together his work on the axiomatisation of set theory. *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

## Sunday, 17 September 2017

### On This Day in Math - September 17

God is a child; and when he began to play, he cultivated mathematics.
It is the most godly of man's games.
~V Erath

The 260th day of the year; 260 is the constant for each row, column and diagonal of the first known(1891) 8x8 bimagic square.
The 8x8 is the smallest order possible for a bimagic square (the squares of the numbers also form a magic square) that uses consecutive digits. The constant for the magic square formed by the squares is 11,180.
More on the first of these in 1891 at the Feb 1 On This Day in Math.

260 is also the sum of the squares of the divisors of 15. /( 260 = 1^2 + 3^2 + 5^2 + 15^2 /)

EVENTS

In 1683, the Dutch scientist Antonie van Leeuwenhoek wrote to the Royal Society reporting his discovery of microscopic living animalcules (live bacteria). He had made observations on the plaque between his own teeth, "a little white matter, which is as thick as if 'twere batter." Looking at these samples with his microscope, Leeuwenhoek reported how in his own mouth: "I then most always saw, with great wonder, that in the said matter there were many very little living animalcules, very prettily a-moving. The biggest sort. . . had a very strong and swift motion, and shot through the water (or spittle) like a pike does through the water. The second sort. . .oft-times spun round like a top. . . and these were far more in number." *TIS

1787 U.S. Constitution signed. Its format was inﬂuenced by the axiomatic approach of Euclidean Geometry. *VFR (I would appreciate insight into what this means? comments? Suggestions? Wild guesses?)

1871 Opening of the Mount Cenis (Fréjus) Tunnel (1857-70) through the Alps, the world's first important mountain tunnel. The two track railway tunnel unites Italian Savoy (north of the mountains) through Switzerland with the rest of Italy to the south. At 8 miles long and it was more than double the length of any previous tunnel. In 1861, after three years of tedious hand-boring a mere eight inches a day into the rock face, Sommeiller introduced the first industrial-scale pneumatics for tunnel digging. He built a special reservoir, high above the tunnel entrance, to produce a head of water that compressed air (to 6 atm.) for pneumatic drills, able to dig up to 20 times faster. Authorized on 15 Aug 1857, the tunnel opened on 17 Sep 1871, as a major triumph of engineering.*TIS

1901 Peter Cooper Hewitt patents the first mercury-vapor lamp.Hewitt was issued U.S. patent #682692 on September 17, 1901. *Wik

1971 RCA withdraws from computer market, losing $490M *CHM 1985 The Los Angeles Times reported that scientists at Chevron tested their new$10 million Cray X­MP supercomputer and discovered the 30th Mersenne Prime and largest known prime (to that date), 2216− 1
*[Part I, pp. 3, 19; Mathematics Magazine

2008, On September 17, a team of researchers at the University of Texas at Dallas led by Founders Professor Hal Sudborough announced the acceptance by the journal Theoretical Computer Science of a more efficient algorithm for pancake sorting than the one proposed by Gates and Papadimitriou in 1979. This establishes a new upper bound of (18/11)n, improving upon the existing bound of (5/3)n from 1979 by William H Gates, soon to be known as Bill Gates of Microsoft, then a Sophomore student at Harvard. *wik

BIRTHS

1743 Marie Jean Antoine Nicolas de Caritat, marquis de Condorcet (17 September 1743 – 28 March 1794), known as Nicolas de Condorcet, was a French philosopher, mathematician, and early political scientist whose Condorcet method in voting tally selects the candidate who would beat each of the other candidates in a run-off election. Unlike many of his contemporaries, he advocated a liberal economy, free and equal public education, constitutionalism, and equal rights for women and people of all races. His ideas and writings were said to embody the ideals of the Age of Enlightenment and rationalism, and remain influential to this day. He died a mysterious death in prison after a period of being a fugitive from French Revolutionary​ authorities.*Wik

1764 John Goodricke (17 Sep 1764; 20 Apr 1786) English astronomer who was the first to notice that some variable stars were periodic. Born a deaf-mute, after a proper education he was able to read lips and to speak. He was the first to calculate the period of Algol to 68 hours and 50 minutes, where the star was changing its brightness by more than a magnitude as seen from Earth. He was also first to correctly propose that the distant sun is periodically occulted by a dark body. John Goodricke was admitted to the Royal Society on 16 April 1786, when 21 years old. He didn't recognized this honor, because he died four days later, in York, from pneumonia.*TIS

1826 (Georg Friedrich) Bernhard Riemann (17 Sep 1826; 20 July 1866) was a German mathematician whose work widely influenced geometry and analysis. In addition, his ideas concerning geometry of space had a profound effect on the development of modern theoretical physics and provided the foundation for the concepts and methods used later in relativity theory. He clarified the notion of integral by defining what we now call the Riemann integral. He was an original thinker and a host of methods, theorems and concepts are named after him. Riemann suffered from tuberculosis and he spent his last years in Italy in an attempt to improve his health. *TIS (A nice cartoon about the Riemann Hypothesis)

1846 Seth Carlo Chandler (17 Sep 1846; 31 Dec 1913) an American astronomer best known for his discovery (1884-85) of the Chandler Wobble, a complex movement in the Earth's axis of rotation (now refered to as polar motion) that causes latitude to vary with a period of 14 months. His interests were much wider than this single subject, however, and he made substantial contributions to such diverse areas of astronomy as cataloging and monitoring variable stars, the independent discovery of the nova T Coronae, improving the estimate of the constant of aberration, and computing the orbital parameters of minor planets and comets. His publications totaled more than 200. *TIS

1857 Konstantin Eduardovich Tsiolkovsky (17 Sep 1857; 19 Sep 1935) Russian pioneer space theorist who, while a provincial Russian schoolteacher, worked out many of the principles of space travel. In 1883, he noted that vehicle in space would travel in the opposite direction to gas that it emitted, and was the first to seriously propose this method propulsion in space travel. He wrote various papers, including the 1903 article "Exploration of Space with Reactive Devices." The engineering equations he derived included parameters such as specific impulse, thrust coefficient and area ratio. He established that the most efficient chemical combination would be that of liquid hydrogen and liquid oxygen. He was later recognized by the Soviet Union as the "father of cosmonautics." He also built the first wind tunnel.*TIS

1905 Hans Freudenthal (September 17, 1905,– October 13, 1990) was a Dutch mathematician. He made substantial contributions to algebraic topology and also took an interest in literature, philosophy, history and mathematics education.
In 1937 he proved the Freudenthal suspension theorem.
Later in his life, Freudenthal focused on elementary mathematics education. In the 1970s, his single-handed intervention prevented the Netherlands from following the worldwide trend of "`new math"'. He was also a fervent critic of one of the first international school achievement studies.
In 1971 he founded the IOWO at Utrecht University, that after his death was renamed Freudenthal Institute, the current Freudenthal institute for science and mathematics education. He was awarded the Gouden Ganzenveer award in 1984, and died in Utrecht in 1990, sitting on a bench in a park where he always took a morning walk.*Wik

1916 Oswald Garrison "Mike" Villard Jr (17 Sep 1916; 7 Jan 2004) American electronics engineer who developed over-the-horizon radar (a way to detect objects out of direct sight by bouncing radar off the ionosphere, an electrically charged layer in the upper atmosphere) so radar could peer around the Earth's curvature to detect aircraft and missiles thousands of miles away. His interest in electricity began with a copy of Harper's Electricity Book for Boys. At age 12, he put together a radio from a kit. During WW II, he researched countermeasures to protect Allied forces against enemy radio and radar devices. He made pioneering studies of radar jamming. In 1947, he designed a simplified voice transmitter permitting two-way communication on a single radio channel, such as a telephone conversation. *TIS

1934 Warren J. Mitofsky, (17 September 1934 - 1 September 2006)While working at the Census Bureau in the 1960s, he and a colleague, Joseph Waksberg, began to devise a random-digit dialing (RDD) system that now bears both their names.
Mr. Mitofsky went to work at CBS News in 1967. Not long afterwards, he organized the first "exit poll" in a Kentucky gubernatorial election, with his first national exit poll being in 1972. He directed the CBS News Election and Survey Unit until 1990, leading, in 1975, to the joint effort with the NYTimes, the CBS News/New York
Times Poll (which The Times calls the New York Times/CBS News Poll),
which he directed until 1990.
Since 2003, Mitofsky, considered the "Father of Exit Polling" by many, led election-night analysis for the News Election Pool, providing exit-poll results and projections. (Mitofsky disliked the term "exit poll"; he preferred "Election Day survey".)
In exit polls on Election Day in 2004, Mitofsky's early exit polls found Senator John Kerry leading over President Bush, which led some in the news media to prepare for Senator Kerry becoming President Kerry. But such was too premature, as Mitofsky readily acknowledged, later discovering that the pro-Kerry exit-poll lead was caused by Republicans refusing to participate at a greater rate than Democrats in the exit polls. [Guess this shows the importance of not ignoring nonresponse.]
However, despite all this, Mitofsky will probably be best remembered by many for his efficient method of sampling telephone numbers using random-digit dialing (RDD), which is now known as the Mitofsky-Waksberg Method. In 1970, Mitofsky wrote an unpublished CBS News memorandum titled "Sampling of Telephone Households" that helped make his name a household word in public-opinion polling. Eight years later, Joseph Waksberg published an analogous paper, "Sampling Methods for Random Digit Dialing", in the prestigious Journal of the American Statistical Association (JASA), thus resulting in the Mitofsky-Waksberg Method appellation.
The Mitofsky-Waksberg Method of RDD is a cluster-sampling method
for sampling residential telephone numbers that greatly increases
the percentage of calls that do reach residential households. *David Bee

DEATHS

1802 Baron Georg von Vega (b. 1754- September 17, 1754), a military officer and mathematician famous for his military campaigns and his table of logarithms, was murdered for “his money and his watch.” [Eves, Adieu, 257◦] *VFR

1823 Abraham-Louis Bréguet (10 Jan 1747, 17 Sep 1823) Swiss-French horologist and inventor who became the leading French watchmaker of his time because of his artistic as well as technical skill. His innovations included a self-winding or "perpétuelle" watch (1780), the gong spring which decreased the size of repeater watches, and the first anti-shock device or "pare-chute", which improved the reliability of his watches while making them less fragile. In 1775 he founded the Breguet watchmaking firm. After a two year interruption during the French Revolution, he continued business with more inventions. He sold the first modern carriage clock to Bonaparte, and created the tact watch by which time could be read by touch.*TIS

1877 William Fox Talbot (11 Feb 1800, 17 Sep 1877) English mathematician, physicist, chemist who invented the negative-positive photographic process. He improved Thomas Wedgewood's discovery (1802) that brushing silver nitrate solution onto paper produces a light-sensitive medium able to record negative images, but Wedgewood was unable to control the darkening. In February 1835, Fox Talbot found that a strong solution of salt fixed the image. Using a camera obscura to focus an image onto his paper to produce a negative, then - by exposing a second sheet of paper to sunlight transmitted through the negative - he was the first to produce a positive picture of which he was able to make further copies at will. His Pencil of Nature (1844) was the first photographically illustrated book. *TIS

1891 Józeph Miksa Petzval (6 Jan 1807, 17 Sept 1891) worked for much of his life on the Laplace transform. He was influenced by the work of Liouville and wrote both a long paper and a two volume treatise on the Laplace transform and its application to ordinary linear differential equations. His study is thorough but not entirely satisfactory since he was unable to use contour integration to invert the transform.
But for a student of Petzval we might today call the Laplace transform the Petzval transform. Petzval fell out with this student who then accused Petzval of plagiarising Laplace's work. Although this was untrue, Boole and Poincaré, influenced no doubt by the quarrel, called the transformation the Laplace transform.
Petzval is best remembered for his work on optical lenses and lens aberration done in the early 1840's (Petzval curvature is named after him) which allowed the construction of modern cameras. Petzval produced an achromatic portrait lens that was vastly superior to the simple meniscus lens then in use. *SAU

1908 Thomas E. Selfridge , a 1903 classmate of Douglas MacArthur at West Point, whose tombstone at West Point reads “Gave up his life in the service of his country at Fort Myers, Virginia, September 17, 1908, falling with the ﬁrst government aeroplane.” The pilot, an Ohio bicycle maker named Orville Wright, survived. [Rick Atkinson, The Long Grey Line (1989), pp. 1–2] (His father was a general, but Selfridge Field, now an Air Natl. Guard base near Detroit, is named for the Lt.,the first person to die in a crash of a powered airplane.)

For more information about Lt. Selfridge and his early relation to flying, the Fort Myers, and Alexander G. Bell, see this great article at the Smithsonian site sent to me by the author, Julia Blakely.

1999 Leonard Carlitz (26 Dec 1907, 17 Sept 1999) Carlitz published 771 papers, supervised 44 doctoral and 51 master's theses. His major mathematical contributions are to finite field theory, number theory, and combinatorics. But his publications extend beyond these areas to include algebraic geometry, commutative rings and algebras, finite differences, geometry, linear algebra, and special functions.*SAU

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