## Sunday, 1 March 2015

### On This Day in Math - March 1

 section of Van Dyke's portrait of della Faille showing mathematical tools *Wik

The role of the teacher is to create the conditions for invention rather than provide ready-made knowledge.
~Seymour Papert

The 60th day of the year; 60 is the smallest composite number which is the order of a simple group.
7! is the smallest # with 60 divisors.

There are four Archimedean solids with 60 vertices , : the truncated icosahedron, (shown) the rhombicosidodecahedron, the snub dodecahedron, and the truncated dodecahedron.

EVENTS
1774 William Herschel begins to keep an astronomical journal, and records observations of Saturn's rings. Herschel's music led him to an interest in mathematics and lenses. His interest in astronomy grew stronger after he made the acquaintance of the English Astronomer Royal Nevil Maskelyne. He started building his own reflecting telescopes and would spend up to 16 hours a day grinding and polishing the speculum metal primary mirrors. He "began to look at the planets and the stars" in May, 1773 and on 1 March 1774 began an astronomical journal by noting his observations of Saturn's rings and the Great Orion Nebula(M4).*Wik

In 1813, Michael Faraday was appointed at the Royal Institution as Chemical Assistant to Humphry Davy, whom he succeeded as Professor of Chemistry in 1820. Since age 14, in 1805, while an apprentice bookbinder, Faraday had educated himself about science. In 1810, he joined the City Philosophical Society to attend lectures and discuss scientific matters. A turning point in his life happened in 1812. A client of the bookbindery gave him four tickets to hear Humphry Davy lecturing at the Royal Institution. Fascinated by the scientific topics, He took notes, which he took with him later to show Davy when he later asked for a position. Davy interviewed him, but there was no opening at the time. When a vacancy occurred in 1813, Davy recalled him and Faraday was hired.*TIS His The Chemical History of a Candle is free from Amazon on Kindle (and quite inexpensive on paper)

1847 On March 1, 1847, Gabriel Lamé announced that he believed that he had found a full proof for Fermat's Last Theorem. He presented to the Paris Academy the outline of what he believed was a complete proof. Earlier he had succeeded in the first proof for x7 + y7 = z7.. The error was later pointed out by Liouville and by Kummer. The error hinged on the assumption of the unique factorization of the roots of unity. Kummer's work on this assumption led to his discovery that unique factorization could be "saved" by using "ideal complex numbers." Kummer's ideal complex numbers would turn out to be a major breakthrough in the generalization of Fermat's Last Theorem. It would also turn out to be the foundation for what is today known as algebraic number theory. *Larry Freeman web page on FLT

1896 Henri Becquerel re-discovers radioactivity. In 1903, together with the Curies, he received the Nobel Prize in Physics for this work. Becquerel thought that phosphorescent materials, such as some uranium salts, might emit penetrating x-ray-like radiation when illuminated by bright sunlight. His first experiments appeared to show this. He presented a paper describing them to the French Academy of Sciences on 24 February 1896
. Then he began to doubt his theory. "I kept the apparatuses prepared and returned the cases to the darkness of a bureau drawer, leaving in place the crusts of the uranium salt. Since the sun did not come out in the following days, I developed the photographic plates on the 1st of March, expecting to find the images very weak. Instead the silhouettes appeared with great intensity.." *Wik

1953 On this date in 1953, Watson and Crick solved the structure of DNA. What better day to lay to rest a few myths about it? *genotopoia Seuagenerian-double-helix

1960 John McCarthy's LISP Programmer's Manual Released :
The first LISP Programmer's Manual is released. Considered the mother tongue of Artificial Intelligence (AI), LISP is older than most other high-level languages still in use today. Its inventor, John McCarthy, created the recursive and symbolic language. *CHM

In 1966, the mission of the Soviet Union's unmanned spacecraft Venera 3 (Venus 3) was a partial success when it reached Venus and automatically released a small landing capsule intended to explore the planet's atmosphere during a parachute descent. However, contact had been lost since 16 Feb 1966. Although no data was returned before the capsule impacted, it became the first man-made object to touch the surface of another planet. The Soviet Union issued a commemorative stamp to mark the achievement. Venera 3 was launched on 16 Nov 1965. The landing capsule (0.9-m diam., about 300-kg) had been designed to collect data on pressure, temperature, and composition of the Venusian atmosphere. Failure is believed due to overheating of internal components and the solar panels.*TIS

1984 The Vatican newspaper, L’Observatore Romano, stated, “The so-called heresy of Galileo does not seem to have any foundation, neither theologically nor under canon law.” In 1822 the church lifted the ban on the works of Galileo and by 1979 Pope John Paul II selected a commission to investigate. On March 1, 1984, the result appeared in the Vatican Newspaper. But it still took until Oct 31, 1992, before Pope John Paul II declared that the church may have been mistaken in condemning Galileo. *Wik

BIRTHS
1597 Jan-Karel della Faille or Jean Charles de La Faille (1 March 1597 in Antwerp, Belgium - 4 Nov 1652 in Barcelona, Spain) was a Flemish Jesuit who was the first to determine the center of gravity of the sector of a circle. He proved that the centers of gravity of a sector of a circle, of a regular figure inscribed in it, of a segment of a circle, or of an ellipse lie on the diameter of the figure. These theorems are founded on a postulate from Luca Valerio's De centro gravitatis solidorum (1604). ... La Faille ended his work with four corollaries which revealed his ultimate goal: an examination of the quadrature of the circle. *SAU

1611 John Pell (1 March 1611 in Southwick, Sussex, England - 12 Dec 1685 in Westminster, London, England) Malcolm wrote, "The mathematician John Pell is a significant figure in the intellectual history of 17th century England - significant, however, more because of his activities, contacts and correspondence than because of his published work. His few publications are, nevertheless, valuable sources of information about his intellectual biography.
Pell worked on algebra and number theory. He gave a table of factors of all integers up to 100000 in 1668.
Pell's equation $y^2 = ax^2 + 1$, where a is a non-square integer, was first studied by Brahmagupta and Bhaskara II. Its complete theory was worked out by Lagrange, not Pell. It is often said that Euler mistakenly attributed Brouncker's work on this equation to Pell. However the equation appears in a book by Rahn which was certainly written with Pell's help: some say entirely written by Pell. Perhaps Euler knew what he was doing in naming the equation. *SAU He introduced the division sign (obelus, ÷) into England. The obelus was first used by Johann Rahn (1622-1676) in 1659 in Teutsche Algebra. Rahn's book was interpreted into English and published, with additions made by John Pell. According to some sources, John Pell was a key influence on Rahn and he may be responsible for the development of the symbol. The word obelus comes from a Greek word meaning a "roasting spit." The symbol wasn't new. It had been used to mark passages in writings that were considered dubious, corrupt or spurious.*TIS

1879 Robert Daniel Carmichael (1 March 1879 in Goodwater, Coosa County, Alabama, USA - 2 May 1967 in Merriam, Northeast Johnson County, Kansas, USA) Carmichael is known for his mathematical research in what are now called the Carmichael numbers (numbers satisfying properties of primes described by Fermat's Little Theorem although they are not primes- see below), Carmichael's theorem, and the Carmichael function, all significant in number theory and in the study of the prime numbers. Carmichael might have been the first to describe the Steiner system S(5,8,24), a structure often attributed to Ernst Witt. While at Indiana University Carmichael was involved with special theory of relativity. *Wik Fermat had proved that if n is prime then xn-1 = 1 mod n for every x coprime to n. A 'Carmichael number' is a non-prime n satisfying this condition for any x coprime to n. It was given this name since Carmichael discovered the first such number, 561, in 1910 (there are several base ten Carmichael numbers below 561 for the interested student to search for). For many years it was an open problem as to whether there were infinitely many Carmichael numbers, but this was settled in 1994 by W R Alford, A Granville, and C Pomerance in their paper There are infinitely many Carmichael numbers. *SAU

1914 I. Bernard Cohen (1 March 1914 – 20 June 2003) was the Victor S. Thomas Professor of the history of science at Harvard University and the author of many books on the history of science and, in particular, Isaac Newton.
Cohen was the first American to receive a Ph.D. in history of science, was a Harvard undergraduate ('37) and then a Ph.D. student and protégé of George Sarton who was the founder of Isis and the History of Science Society. Cohen taught at Harvard from 1942 until his death, and his tenure was marked by the development of Harvard's program in the history of science. *Wik

1928 Seymour Papert (1 Mar 1928, )American computer scientist who invented the Logo computer programming language, an educational computer programming language for children. He studied under Piaget, absorbing his educational theories. He has studied ways to use mathematics to understand better how children learn and think, and about the ways in which computers can aid in a child's learning. With Marvin Minsky, he co-founded the Artificial Intelligence Lab at MIT. In the mid-80's he worked in Costa Rica to develop a nationwide program of intensive computer use throughout the public education system. Costa Rica, which now has the highest literacy rate in the Americas, continues to serve as a model for large-scale deployment of computer technology in education.*TIS

DEATHS
1862 Peter Barlow (13 Oct 1776 Norwich, UK; 1 Mar 1862) English mathematician and engineer who invented two varieties of achromatic (non-colour-distorting) telescope lenses. In 1819, Barlow began work on the problem of deviation in ship compasses caused by the presence of iron in the hull. For his method of correcting the deviation by juxtaposing the compass with a suitably shaped piece of iron, he was awarded the Copley Medal. In 1822, he built a device which is to be considered one of the first models of an electric motor supplied by continuous current. He also worked on the design of bridges, in particular working (1819-26) with Thomas Telford on the design of the bridge over the Menai Strait, the first major modern suspension bridge. Barlow was active during the period of railway building in Britain.*TIS His New Mathematical Tables (1814) later known as Barlow’s Tables, gave the factors, squares, cubes, square roots, reciprocals, and natural logarithms of all numbers from 1 to 10,000. It was so accurate that it was reprinted numerous times, the last being 1947. *VFR

1884 Isaac Todhunter (23 Nov 1820 in Rye, Sussex, England - 1 March 1884 in Cambridge, England) Todhunter is best known for his textbooks and his writing on the history of mathematics. Among his textbooks are Analytic Statics (1853), Plane Coordinate Geometry (1855), Examples of Analytic geometry in Three Dimensions (1858). He also wrote some more elementary texts, for example Algebra (1858), Trigonometry (1859), Theory of Equations (1861), Euclid (1862), Mechanics (1867) and Mensuration (1869).
Among his books on the history of mathematics are A History of the Mathematical Theory of Probability from the Time of Pascal to that of Laplace (1865, reprinted 1965) and History of the Mathematical Theories of Attraction (1873). No mathematical treatises on elementary subjects probably ever attained so wide a circulation; and, being adopted by the Indian government, they were translated into Urdu and other Oriental languages.
Todhunter received many awards for his contributions to mathematics. In addition to the fellowship of the Royal Society he served on its Council in 1874, the same year in which he was awarded the Adams Prize for his work Researches on the calculus of variations.*SAU

1908 Heinrich Maschke (24 October 1853 in Breslau, Germany (now Wrocław, Poland) – 1 March 1908 Chicago, Illinois, USA) was a German mathematician who proved Maschke's theorem, a theorem in group representation theory that concerns the decomposition of representations of a finite group into irreducible pieces.*Wik
1913 Mario Pieri (22 June 1860 in Lucca, Italy - 1 March 1913 in S Andrea di Compito (near Lucca), Italy) Pieri's main area was projective geometry and he is an important member of the Italian School of Geometers. However, after he moved to Turin, Pieri became influenced by Peano at the University and Burali-Forti who was a colleague at the Military Academy. This influence led Pieri to study the foundations of geometry.
In 1895 he set up an axiomatic system for projective geometry with three undefined terms, namely points, lines and segments. He improved on results of Pasch and Peano and then, in 1905, Pieri gave the first axiomatic definition of complex projective geometry which does not build on real projective geometry.
In 1898 Pieri published the memoir The principles of the geometry of position through the Academy of Sciences of Turin. Russell was impressed by this memoir and wrote, in his Principia, "This is, in my opinion, the best work on the present subject." *SAU

1978 Kiyoshi Oka (April 19, 1901 – March 1, 1978) was a Japanese mathematician who did fundamental work in the theory of several complex variables. He was born in Osaka. He went to Kyoto Imperial University in 1919, turning to mathematics in 1923 and graduating in 1924.
He was in Paris for three years from 1929, returning to Hiroshima University. He published solutions to the first and second Cousin problems, and work on domains of holomorphy, in the period 1936–1940. These were later taken up by Henri Cartan and his school, playing a basic role in the development of sheaf theory. Oka continued to work in the field, and proved Oka's coherence theorem in 1950.
He was professor at Nara Women's University from 1949 to retirement at 1964. He received many honours in Japan.*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

## Saturday, 28 February 2015

### On This Day in Math - February 28

Well David, I have a lot of ideas and throw away the bad ones.
Upon being asked how he had so many good ideas by David Harker, his student.
— Linus Pauling

The 59th day of the year; 59 is the center prime number in a 3x3 prime magic square that has the smallest possible total for each row, column and diagonal, 177. (Can you find the other eight primes and their positions in this magic square?)
59 divides the smallest composite Euclid number 13# + 1= 13*11*7*5*2 + 1 = 59*509  (the symbol for a primorial,  n#, means the product of all primes from n down to 2)

And at the right is one of the 59 stellations of the icosahedron.
Now for some nice observations from Derek Orr@MathYearRound:
5^59 - 4^59 is prime.
4^59 - 3^59 is prime.
3^59 - 2^59 is prime.
The first 59 digits of 58^57 form a prime.

EVENTS
1678 In a letter to Robert Boyle, Isaac Newton explained his concept of ether. “I suppose that there is diffused through all places an ethereal substance capable of contraction and dilation, strongly elastic and, in a word, much like air in all respects, but far more subtil.” He thought it was in all bodies of matter, but "rarer in the pores than in free spaces." This he suspects is the cause of light being refracted towards the perpendicular. *Rigaud, Letters of Scientiﬁc men, vol. 2, p. 407

1695 Liebniz writes to Johann Bernoulli encouraging him to use the term calculus summatorus which Liebniz used for integration.

*VFR

1825 Cauchy presented to the Acad´emie a paper on integals of complex-valued functions where the limits of integration were allowed to be complex. Previously, he had done much work on such
integrals when the limits were real. [Grattan-Guinness, 1990, p. 766] *VFR

1953, James Watson, from early on this Saturday, spent his time at the Cavendish Laboratory in Cambridge, shuffling cardboard cutout models of the molecules of the DNA bases: adenine (A), guanine (G), cytosine (C) and thymine(T). After a while, in a spark of ingenuity, he discovered their complementary pairing. He realized that A joined with T had a close resemblance to C joined with G, and that each pair could hold together with hydrogen bonds. Such pairs could also neatly fit like rungs meeting at right-angles between two anti-parallel helical sugar-phosphate backbones of DNA wound around a common axis. Such structure was consistent with the known X-ray diffraction pattern evidence. Each separated helix with its half of the pairs could form a template for reproducing the molecule. The secret of life First announcement by Francis Crick and James Watson that they had reached their conclusion about the double helix structure of the DNA molecule. Their paper, A Structure for Deoxyribose Nucleic Acid, was published in the 25 Apr 1953 issue of journal Nature. *TIS

1956 Jay Forrester at MIT is awarded a patent for his coincident current magnetic core memory. Forrester's invention, given Patent No. 2,736,880 for a "multicoordinate digital information storage device," became the standard memory device for digital computers until supplanted by solid state (semiconductor) RAM in the mid-1970s. *CHM

2001 With a length of 350 feet 6.6 inches and currently the World's Longest documented Slide Rule, The Texas Magnum by Skip Solberg and Jay Francis,was demonstrated on February 28, 2001 in the Lockeed-Martin Aircraft Assembly Facility at Air Force Plant 4 in Fort Worth, Texas. The Texas Magnum holds the world's record for the longest linear slide rule. The Texas Magnum was designed as a traditional Mannheim style slide rule. The A, C, D and L scales are included on the slide rule *International Slide Rule Museum

BIRTHS

1552 Joost Bürgi (28 Feb 1552, 31 Jan 1632) Swiss watchmaker and mathematician who invented logarithms independently of the Scottish mathematician John Napier. He was the most skilful, and the most famous, clockmaker of his day. He also made astronomical and practical geometry instruments (notably the proportional compass and a triangulation instrument useful in surveying). This led to becoming an assistant to the German astronomer Johannes Kepler. Bürgi was a major contributor to the development of decimal fractions and exponential notation, but his most notable contribution was published in 1620 as a table of antilogarithms. Napier published his table of logarithms in 1614, but Bürgi had already compiled his table of logarithms at least 10 years before that, and perhaps as early as 1588. *TIS

1704 Louis Godin (28 February 1704 Paris – 11 September 1760 Cadiz) was a French astronomer and member of the French Academy of Sciences. He worked in Peru, Spain, Portugal and France.
He was graduated at the College of Louis le Grand, and studied astronomy under Joseph-Nicolas Delisle. His astronomical tables (1724) gave him reputation, and the French Academy of Sciences elected him a pensionary member. He was commissioned to write a continuation of the history of the academy, left uncompleted by Bernard le Bovier de Fontenelle, and was also authorized to submit to the minister, Cardinal André-Hercule de Fleury, the best means of discovering the truth in regard to the figure of the earth, and proposed sending expeditions to the equator and the polar sea. The minister approved the plan and appropriated the necessary means, the academy designating Charles Marie de La Condamine, Pierre Bouguer, and Godin to go to Peru in 1734.
When they had finished their task in 1738, at the invitation of the Viceroy of Peru, Godin accepted the professorship in mathematics in Lima, where he also established a course of astronomical lectures. When in 1746 an earthquake destroyed the greater part of Lima, he took valuable seismological observations, assisted the sufferers, and made plans by the use of which the new buildings would be less exposed to danger from renewed shocks.
In 1751 he returned to Europe, but found that he had been nearly forgotten, and superseded as pensioner of the academy; and, as his fortune had been lost in unfortunate speculations, he accepted the presidency of the college for midshipmen in Cadiz in 1752. During the earthquake of Lisbon, 1755, which was distinctly felt at Cadiz, he took observations and did much to allay the apprehensions of the public, for which he was ennobled by the king of Spain. In 1759 he was called to Paris and reinstated as pensionary member of the academy, but he died on his return to Cadiz. *Wik

1735 Alexandre-Théophile Vandermonde (28 Feb 1735 in Paris, France - 1 Jan 1796 in Paris, France). was a French mathematician best known for his work on determinants. *SAU
In 1772 Vandermonde used [P]n to represent the product of the n factors p(p-1)(p-2)... (p-n+1). With such a notation [P]p would represent what we would now write as p!, but I can imagine this becoming, over time, just [p] (De Morgan would do just such a thing in his 1838 essays on probability). Vandermonde seems to have been the first to consider [p]0 (or 0!) and determined it was (as we now do) equal to one. Vandermonde's notation included a method for skipping numbers, so that [p/3]n would indicate p(p-3)(p-6)... (p-3(n-1)). (this method seems better to me than the present method for factorials which skip terms) It even allowed for negative exponents.

1859 Florian Cajori (born 28 Feb 1859)Swiss-born U.S. educator and mathematician whose works on the history of mathematics were among the most eminent of his time.*TIS at times Cajori's work lacked the scholarship which one would expect of such an eminent scientist, we must not give too negative an impression of this important figure. He almost single-handedly created the history of mathematics as an academic subject in the United States and, particularly with his book on the history of mathematical notation, he is still one of the most quoted historians of mathematics today. *SAU

1878 Pierre Joseph Louis Fatou (28 Feb 1878 in Lorient, France - 10 Aug 1929 in Pornichet, France) was a French mathematician working in the field of complex analytic dynamics. He entered the École Normale Supérieure in Paris in 1898 to study mathematics and graduated in 1901 when he was appointed an astronomy post in the Paris Observatory. Fatou continued his mathematical explorations and studied iterative and recursive processes such as z == z2+C . the Julia set and the Fatou set are two complementary sets defined from a function.
Fatou wrote many papers developing a Fundamental theory of iteration in 1917, which he published in the December 1917 part of Comptes Rendus. His findings were very similar to those of Gaston Maurice Julia, who submitted a paper to the Académie des Sciences in Paris for their 1918 Grand Prix on the subject of iteration from a global point of view. Their work is now commonly referred to as the generalised Fatou–Julia theorem.*Wik  Fatou dust is a term applied to certain iteration sets that have zero area and an infinite number of disconnected components.

1901 Linus Carl Pauling (28 Feb 1901; 19 Aug 1994 at age 93) an American chemist, physicist and author who applied quantum mechanics to the study of molecular structures, particularly in connection with chemical bonding. Pauling was awarded the Nobel Prize for Chemistry in 1954 for charting the chemical underpinnings of life itself. Because of his work for nuclear peace, he received the Nobel Prize for Peace in 1962. He is remembered also for his strong belief in the health benefits of large doses of vitamin C.*TIS

1925 Louis Nirenberg (28 February 1925, Hamilton, Ontario, Canada - ) is a Canadian-born American mathematician, and one of the outstanding analysts of the twentieth century. He has made fundamental contributions to linear and nonlinear partial differential equations and their application to complex analysis and geometry.*Wik

1930 Leon N. Cooper (28 Feb 1930 - ) American physicist who shared (with John Bardeen and John Robert Schrieffer) the 1972 Nobel Prize in Physics, for his role in developing the BCS (for their initials) theory of superconductivity. The concept of Cooper electron pairs was named after him.*Wik

1939 Daniel C. Tsui (28 Feb 1939 - ) Chinese-American physicist who shared (with Horst L. Störmer and Robert B. Laughlin) received the 1998 Nobel Prize for Physics for the discovery and explanation that the electrons in a powerful magnetic field at very low temperatures can form a quantum fluid whose particles have fractional electric charges. This effect is known as the fractional quantum. *TIS

1954 Jean Bourgain(28 Feb 1954 - )Belgian mathematician who was awarded the Fields Medal in 1994 for his work in analysis. His achievements in several fields included the problem of determining how large a section of a Banach space of finite dimension n can be found that resembles a Hilbert subspace; a proof of Luis Antonio Santaló's inequality; a new approach to some problems in ergodic theory; results in harmonic analysis and classical operators; and nonlinear partial differential equations. Bourgain's work was noteworthy for the versatility it displayed in applying ideas from wide-ranging mathematical disciplines to the solution of diverse problems. *TIS

DEATHS
1691 Joseph Moxon (8 August 1627 - February 1691 (Royal Society archives state his death date as 28 February; the Oxford Dictionary of National Biography states that he was buried on 15 February???{I hope one of them was wrong}), hydrographer to Charles II, was an English printer of mathematical books and maps, a maker of globes and mathematical instruments, and mathematical lexicographer. He produced the first English language dictionary devoted to mathematics, "Mathematicks made easie, or a mathematical dictionary, explaining the terms of art and difficult phrases used in arithmetick, geometry, astronomy, astrology, and other mathematical sciences". In November 1678, he became the first tradesman to be elected as a Fellow of the Royal Society. *Wik Thony Christie has written that he was one of the first English Printers to print tables of Logarithms.

1742 Willem 'sGravesande (26 September 1688 – 28 February 1742)was a Dutch mathematician who expounded Newton's philosophy in Europe. In 1717 he became professor in physics and astronomy in Leiden, and introduced the works of his friend Newton in the Netherlands.
His main work is Physices elementa mathematica, experimentis confirmata, sive introductio ad philosophiam Newtonianam or Mathematical Elements of Natural Philosophy, Confirm'd by Experiments (Leiden 1720), in which he laid the foundations for teaching physics. Voltaire and Albrecht von Haller were in his audience, Frederic the Great invited him in 1737 to come to Berlin.
His chief contribution to physics involved an experiment in which brass balls were dropped with varying velocity onto a soft clay surface. His results were that a ball with twice the velocity of another would leave an indentation four times as deep, that three times the velocity yielded nine times the depth, and so on. He shared these results with Émilie du Châtelet, who subsequently corrected Newton's formula E = mv to E = mv2. (Note that though we now add a factor of 1/2 to this formula to make it work with coherent systems of units, the formula as expressed is correct if you choose units to fit it.) *Wik

1863 Jakob Philipp Kulik (1 May 1793 in Lemberg, Austrian Empire (now Lviv, Ukraine) - 28 Feb 1863 in Prague, Czech Republic) Austrian mathematician known for his construction of a massive factor tables.
Kulik was born in Lemberg, which was part of the Austrian empire, and is now Lviv located in Ukraine.In 1825, Kulik mentioned a table of factors up to 30 millions, but this table does no longer seem to exist. It is also not clear if it had really been completed.
From about 1825 until 1863 Kulik produced a factor table of numbers up to 100330200 (except for numbers divisible by 2, 3, or 5). This table basically had the same format that the table to 30 millions and it is therefore most likely that the work on the "Magnus canon divisorum" spanned from the mid 1820s to Kulik's death, at which time the tables were still unfinished. These tables fill eight volumes totaling 4212 pages, and are kept in the archives of the Academy of Sciences in Vienna. Volume II of the 8 volume set has been lost.*Wik

1956 Frigyes Riesz (22 Jan 1880; 28 Feb 1956) Hungarian mathematician and pioneer of functional analysis, which has found important applications to mathematical physics. His theorem, now called the Riesz-Fischer theorem, which he proved in 1907, is fundamental in the Fourier analysis of Hilbert space. It was the mathematical basis for proving that matrix mechanics and wave mechanics were equivalent. This is of fundamental importance in early quantum theory. His book Leçon's d'analyse fonctionnelle (written jointly with his student B Szökefalvi-Nagy) is one of the most readable accounts of functional analysis ever written. Beyond any mere abstraction for the sake of a structure theory, he was always turning back to the applications in some concrete and substantial situation. *TIS

2013 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 behaviour 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. *Philosopy of Science Portal

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

## Friday, 27 February 2015

### On This Day in Math - February 27

 Andromeda Galaxy which Hubble measured to be 300,000 parsecs away.

Mathematical Knowledge adds a manly Vigour to the Mind, frees it from Prejudice, Credulity, and Superstition.
~John Arbuthnot

The 58th day of the year; 58 is  the sum of the first seven prime numbers. It is the fourth smallest Smith Number. (Find the first three. A Smith number is a composite number for which the sum of its digits equals the sum of the digits in its prime factorization, including repetition. 58 = 2*29, and 5+8= 2+2+9.) Smith numbers were named by Albert Wilansky of Lehigh University. He noticed the property in the phone number (493-7775) of his brother-in-law Harold Smith.

If you take the number 2, square it, and continue to take the sum of the squares of the digits of the previous answer, you get the sequence 2, 4, 16, 37, 58, 89, 145, 42, 20, 4, and then it repeats.  See what happens if you start with other values than 2, and see if you can find one that doesn't produce 58.

EVENTS
425 "University" or Pandidakterion of Constantinople Founded on this date by Theodosius II. It is described as "the first deliberate effort of the Byzantine state to impose its control on matters relating to higher education." *Wik *Medieval History ‏@medievalhistory
1477 Founding of the University of Uppsala. A research university in Uppsala, Sweden, and is the oldest university in Sweden and Northern Europe. It ranks among the best universities in Northern Europe and is generally considered one of the most prestigious institutions of higher learning in Europe. Prominent students include Carolus Linnaeus , the father of taxonomy; Anders Celsius, inventor of the centigrade scale, and Niklas Zennström, co-founder of KaZaA and Skype. *Wik

In 1611, Johannes Fabricius, a Dutch astronomer, observed the rising sun through his telescope, and observed several dark spots on it. This was perhaps the first ever observation of sunspots. He called his father to investigate this new phenomenon with him. The brightness of the Sun's center was very painful, and the two quickly switched to a projection method by means of a camera obscura. Johannes was the first to publish information on such observations. He did so in his Narratio de maculis in sole observatis et apparente earum cum sole conversione. ("Narration on Spots Observed on the Sun and their Apparent Rotation with the Sun"), the dedication of which was dated 13 Jun 1611. *TIS

1665 Huygens writes letter to Robert Moray at the Royal Society asking him to pass on his "miraculous" observation of a synchronizing of his pendulum clocks. (See Feb 25). *Steven Strogatz, Synch

1890 Dedekind’s second letter to Keferstein. Hans Keferstein had published a paper on the notion of number with comments and suggestions for change of Dedekind's 1888 book. Dedekind first responded on February 9, and on February 14 and announced that he would push the publication by the "Society". It was in the letter of February 27 that Dedekind gives what is called, "a brilliant presentation of the development of his ideas on the notion of natural number." *Jean Van Heijenoort, From Frege to Gödel: a source book in mathematical logic, 1879-1931, pg 98 The text of the letter is available on-line at Google Books

1924, Harlow Shapley wrote replied to a letter from Edwin Hubble which presented the measurement of 300,000 parsecs as the distance to the Andromeda nebula. That was the first proof that the nebula was far outside the Milky Way, in fact, a separate galaxy. When Shapley had debated Heber Curtis on 26 Apr 1920, he presented his firm, life-long conviction that all the Milky Way represented the known universe (and, for instance, the Andromeda nebula was part of the Milky Way.) On receipt of the letter, Shapley told Payne-Gaposchkin and said “Here is the letter that has destroyed my universe.” In his reply, Shapley said sarcastically that Hubble's letter was “the most entertaining piece of literature I have seen for a long time.” Hubble sent more data in a paper to the AAS meeting, read on 1 Jan 1925. *TIS

1936 France issued a stamp with a portrait (by Louis Boilly) of Andr´e-Marie Amp`ere (1775–1836) to honor the centenary of his death. [Scott #306] *VFR

1942, J.S. Hey discovered radio emissions from the Sun. *TIS Several prior attempts were made to detect radio emission from the Sun by experimenters such as Nikola Tesla and Oliver Lodge, but those attempts were unable to detect any emission due to technical limitations of their instruments. Jansky first thought the radio signals he picked up from space were from the sun. *Wik

1989 In a review of Einstein–Bessso correspondence in the New Yorker, Jeremy Bernstein wrote: “In 1909, Einstein accepted a job as an associate professor at the University of Zurich, ... Einstein makes a familiar academic complaint—that because of his teaching duties he has less free time than when he was examining patents for eight hours a day.” *VFR

BIRTHS
1547 Baha' ad-Din al-Amili (27 Feb 1547 in Baalbek, now in Lebanon - 30 Aug 1621 in Isfahan, Iran) was a Lebanese-born mathematician who wrote influential works on arithmetic, astronomy and grammar. Perhaps his most famous mathematical work was Quintessence of Calculation which was a treatise in ten sections, strongly influenced by The Key to Arithmetic (1427) by Jamshid al-Kashi. *SAU

1881 L(uitzen) E(gbertus) J(an) Brouwer (27 Feb 1881, 2 Dec 1966) was a Dutch mathematician who founded mathematical Intuitionism (a doctrine that views the nature of mathematics as mental constructions governed by self-evident laws). He founded modern topology by establishing, for example, the topological invariance of dimension and the fixpoint theorem. (Topology is the study of the most basic properties of geometric surfaces and configurations.) The Brouwer fixed point theorem is named in his honor. He proved the simplicial approximation theorem in the foundations of algebraic topology, which justifies the reduction to combinatorial terms, after sufficient subdivision of simplicial complexes, the treatment of general continuous mappings. *TIS He denies the law of the excluded middle. *VFR

1897 Bernard(-Ferdinand) Lyot (27 Feb 1897; 2 Apr 1952 at age 55) French astronomer who invented the coronagraph (1930), an instrument which allows the observation of the solar corona when the Sun is not in eclipse. Earlier, using his expertise in optics, Lyot made a very sensitive polariscope to study polarization of light reflected from planets. Observing from the Pic du Midi Observatory, he determined that the lunar surface behaves like volcanic dust, that Mars has sandstorms, and other results on the atmospheres of the other planets. Modifications to his polarimeter created the coronagraph, with which he photographed the Sun's corona and its analyzed its spectrum. He found new spectral lines in the corona, and he made (1939) the first motion pictures of solar prominences.*TIS

1910 Joseph Doob (27 Feb 1910 in Cincinnati, Ohio, USA - 7 June 2004 in Clark-Lindsey Village, Urbana, Illinois, USA) American mathematician who worked in probability and measure theory. *SAU After writing a series of papers on the foundations of probability and stochastic processes including martingales, Markov processes, and stationary processes, Doob realized that there was a real need for a book showing what is known about the various types of stochastic processes. So he wrote his famous "Stochastic Processes" book. It was published in 1953 and soon became one of the most influential books in the development of modern probability theory. *Wik

1942 Robert (Bob) Howard Grubbs (b. 27 February 1942 near Possum Trot, Kentucky, ) is an American chemist and Nobel laureate. Grubbs's many awards have included: Alfred P. Sloan Fellow (1974–76), Camille and Henry Dreyfus Teacher-Scholar Award (1975–78), Alexander von Humboldt Fellowship (1975), ACS Benjamin Franklin Medal in Chemistry (2000), ACS Herman F. Mark Polymer Chemistry Award (2000), ACS Herbert C. Brown Award for Creative Research in Synthetic Methods (2001), the Tolman Medal (2002), and the Nobel Prize in Chemistry (2005). He was elected to the National Academy of Sciences in 1989 and a fellowship in the American Academy of Arts and Sciences in 1994. Grubbs received the 2005 Nobel Prize in Chemistry, along with Richard R. Schrock and Yves Chauvin, for his work in the field of olefin metathesis. *Wik

DEATHS
1735 John Arbuthnot (baptized 29 Apr 1667, 27 Feb 1735 at age 67), fellow of the Royal College of Physicians. In 1710, his paper “An argument for divine providence taken form the constant regularity observ’s in the bith of both sexes” gave the ﬁrst example of statistical inference. In his day he was famous for his political satires, from which we still know the character John Bull. *VFR
He inspired both Jonathan Swift's Gulliver's Travels book III and Alexander Pope's Peri Bathous, Or the Art of Sinking in Poetry, Memoirs of Martin Scriblerus. He also translated Huygens' "De ratiociniis in ludo aleae " in 1692 and extended it by adding a few further games of chance. This was the first work on probability published in English.*SAU A nice blog about Arbuthnot and his work is at this post by *RMAT.

1867 James Dunwoody Brownson DeBow (1820 – February 27, 1867) was an American publisher and statistician, best known for his influential magazine DeBow's Review, who also served as head of the U.S. Census from 1853-1857.*Wik

1906 Samuel Pierpont Langley, (22 Aug 1834; 27 Feb 1906)American astronomer, physicist, and aeronautics pioneer who built the first heavier-than-air flying machine to achieve sustained flight. He launched his Aerodrome No.5 on 6 May 1896 using a spring-actuated catapult mounted on top of a houseboat on the Potomac River, near Quantico, Virginia. He also researched the relationship of solar phenomena to meteorology. *TIS

1915 Nikolay Yakovlevich Sonin (February 22, 1849 – February 27, 1915) was a Russian mathematician.
Sonin worked on special functions, in particular cylindrical functions. He also worked on the Euler–Maclaurin summation formula. Other topics Sonin studied include Bernoulli polynomials and approximate computation of definite integrals, continuing Chebyshev's work on numerical integration. Together with Andrey Markov, Sonin prepared a two volume edition of Chebyshev's works in French and Russian. He died in St. Petersburg.*Wik

1975 Hyman Levy (28 Feb 1889 in Edinburgh, Scotland - 27 Feb 1975 in Wimbledon, London, England )graduated from Edinburgh and went on to study in Göttingen. He was forced to leave Germany on the outbreak of World War II and returned to work at Oxford and at the National Physical Laboratory. He held various posts in Imperial College London, finishing as Head of the Mathematics department. His main work was in the numerical solution of differential equations. he published Numerical Studies in Differential Equations (1934), Elements of the Theory of Probability (1936), and Finite Difference Equations (1958). However, Levy was more than a mathematician. He was a philosopher of science and also a political activist. *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, 26 February 2015

### On This Day in Math - February 26

Euler calculated without effort,
just as men breathe,
as eagles sustain themselves in the air.
~Francois Arago

The 57th day of the year; 57(base ten) is written with all ones in base seven. It is the last day this year that can be written in base seven with all ones.(What is the last day of the year that can be written with all ones in base two,... base three?)

EVENTS
1616 Galileo is warned to abandon Copernican views. On February 19, 1616, the Inquisition had asked a commission of theologians, known as qualifiers, about the propositions of the heliocentric view of the universe after Nicollo Lorin had accused Galileo of Heretical remarks in a letter to his former student, Benedetto Castelli. On February 24 the Qualifiers delivered their unanimous report: the idea that the Sun is stationary is "foolish and absurd in philosophy, and formally heretical since it explicitly contradicts in many places the sense of Holy Scripture..."; while the Earth's movement "receives the same judgement in philosophy and ... in regard to theological truth it is at least erroneous in faith."At a meeting of the cardinals of the Inquisition on the following day, Pope Paul V instructed Bellarmine to deliver this result to Galileo, and to order him to abandon the Copernican opinions; should Galileo resist the decree, stronger action would be taken. On February 26, Galileo was called to Bellarmine's residence, and accepted the orders. *Wik A transcript filed by the 1633 Inquisition indicates he was also enjoined from either speaking or writing about his theory. Yet Galileo remained in conflict with the Church. He was eventually interrogated by the Inquisition in Apr 1633. On 22 Jun 1633, Galileo was sentenced to prison indefinitely, with seven of ten cardinals presiding at his trial affirming the sentencing order. Upon signing a formal recantation, the Pope allowed him to live instead under house-arrest. From Dec 1633 to the end of his life on 8 Jan 1641, he remained in his villa at Florence.*TIS In 1992, the Vatican officially declared that Galileo had been the victim of an error.

1665 A letter from Christiaan Huygens to his father, Constantyn Huygens describes the discovery of synchronization between two pendulum clocks in his room.
While I was forced to stay in bed for a few days and made observations on my two clocks of the new workshop, I noticed a wonderful effect that nobody could have thought of before. The two clocks, while hanging [on the wall] side by side with a distance of one or two feet between, kept in pace relative to each other with a precision so high that the two pendulums always swung together, and never varied. While I admired this for some time, I finally found that this happened due to a sort of sympathy: when I made the pendulums swing at differing paces, I found that half an hour later, they always returned to synchronism and kept it constantly afterwards, as long as I let them go.

1849 Prince Albert visited the Ri for the 1st time to hear a lecture by Faraday. *Royal Institution ‏@ri_science Image

1855 Carl F. Gauss' body lay in state under the dome in the rotunda of the observatory in Gottingen two days after his death.  At nine o'clock a group of 12 students of science and mathematics, including Dedikind, carried the coffin out of the observatory and to his final resting place in St. Alben's Church Cemetary. After the casket was lowered it was covered with  covered with palms and laurel .

1885 “The Burroughs Company brought out their ﬁrst adding machine and announced that it would sell for $27.75$ plus $1.39$ shipping charges, for a total of whatever that came to.” *Tom Koch, 366 Dumb Days in History by Tom Koch

1962 A new teaching method based on “how and why things happen in mathematics rather than on traditional memorization of rules” is announced by the Educational Research Council of Greater Cleveland. This became the Cleveland Program of the New Math.*VFR

In 1896, Henri Becquerel stored a wrapped photographic plate in a closed desk drawer, and a phosphorescent uranium compound laid on top, awaiting a bright day to test his idea that sunlight would make the phosphorescent uranium emit rays. It remained there several days. Thus by sheer accident, he created a new experiment, for when he developed the photographic plate on 1 Mar 1896, he found a fogged image in the shape of the rocks. The material was spontaneously generating and emitting energetic rays totally without the external sunlight source. This was a landmark event. The new form of penetrating radiation was the discovery of the effect of radioactivity. He had in fact reported an earlier, related experiment to the French Academy on 24 Feb 1896, though at that time he thought phosphorescence was the cause.*TIS

1996 Silicon Graphics Inc. buys Cray Research for \$767 million, becoming the leading supplier of high-speed computing machines in the U.S. Over a forty year career, Cray founder Seymour Cray consistently produced most of the fastest computers in the world-- innovative, powerful supercomputers used in defense, meteorological, and scientific investigations. *CHM

2012 New world record distance for paper airplane throw: Joe Ayoob, a former Cal Quaterback, throws a John Collins paper airplane design, (which was named Suzanne), officially breaking the world record by 19 feet, 6 inches. The new world record was 226 feet, 10 inches. The previous record is 207 feet and 4 inches set by Stephen Kreiger in 2003. *ESPN

BIRTHS
1585 Federico Cesi (26 Feb OR 13 Mar 1585 (sources differ, but Thony Christie did some research to suggest the Feb date is the correct one); 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.

1664 Nicolas Fatio de Duillier (alternative names are Facio or Faccio;) (26 February 1664 – 12 May 1753) was a Swiss mathematician known for his work on the zodiacal light problem, for his very close (some have suggested "romantic" ) relationship with Isaac Newton, for his role in the Newton v. Leibniz calculus controversy , and for originating the "push" or "shadow" theory of gravitation.
[Le Sage's theory of gravitation is a kinetic theory of gravity originally proposed by Nicolas Fatio de Duillier in 1690 and later by Georges-Louis Le Sage in 1748. The theory proposed a mechanical explanation for Newton's gravitational force in terms of streams of tiny unseen particles (which Le Sage called ultra-mundane corpuscles) impacting all material objects from all directions. According to this model, any two material bodies partially shield each other from the impinging corpuscles, resulting in a net imbalance in the pressure exerted by the impact of corpuscles on the bodies, tending to drive the bodies together.]

He also developed and patented a method of perforating jewels for use in clocks.
When Leibniz sent a set of problems for solution to England he mentioned Newton and failed to mention Faccio among those probably capable of solving them. Faccio retorted by sneering at Leibniz as the ‘second inventor’ of the calculus in a tract entitled ‘Lineæ brevissimæ descensus investigatio geometrica duplex, cui addita est investigatio geometrica solidi rotundi in quo minima fiat resistentia,’ 4to, London, 1699. Finally he stirred up the whole Royal Society to take a part in the dispute (Brewster, Memoirs of Sir I. Newton, 2nd edit. ii. 1–5).
In 1707, Fatio came under the influence of a fanatical religious sect, the Camisards, which ruined Fatio's reputation. He left England and took part in pilgrim journeys across Europe. After his return only a few scientific documents by him appeared. He died in 1753 in Maddersfield near Worcester, England. After his death his Geneva compatriot Georges-Louis Le Sage tried to purchase the scientific papers of Fatio. These papers together with Le Sage's are now in the Library of the University of Geneva.
Eventually he retired to Worcester, where he formed some congenial friendships, and busied himself with scientific pursuits, alchemy, and the mysteries of the cabbala. In 1732 he endeavoured, but it is thought unsuccessfully, to obtain through the influence of John Conduitt [q. v.], Newton's nephew, some reward for having saved the life of the Prince of Orange. He assisted Conduitt in planning the design, and writing the inscription for Newton's monument in Westminster Abbey. *Wik

1786 Dominique François Jean Arago (26 Feb 1786, 2 Oct 1853) was a French physicist and astronomer who discovered the chromosphere of the sun (the lower atmosphere, primarily composed of hydrogen gas), and for his accurate estimates of the diameters of the planets. Arago found that a rotating copper disk deflects a magnetic needle held above it showing the production of magnetism by rotation of a nonmagnetic conductor. He devised an experiment that proved the wave theory of light, showed that light waves move more slowly through a dense medium than through air and contributed to the discovery of the laws of light polarization. Arago entered politics in 1848 as Minister of War and Marine and was responsible for abolishing slavery in the French colonies. *TIS A really great blog about Arago, With the catchy title, "François Arago: the most interesting physicist in the world!" is posted here. Read this introduction, and you will not be able to resist:

When he was seven years old, he tried to stab a Spanish solider with a lance
When he was eighteen, he talked a friend out of assassinating Napoleon
He once angered an archbishop so much that the holy man punched him in the face
He has negotiated with bandits, been chased by a mob, broken out of prison
He is:
François Arago, the most interesting physicist in the world

1799 Benoit Clapeyron (26 Feb 1799, 28 Jan 1864) French engineer who expressed Sadi Carnot's ideas on heat analytically, with the help of graphical representations. While investigating the operation of steam engines, Clapeyron found there was a relationship (1834) between the heat of vaporization of a fluid, its temperature and the increase in its volume upon vaporization. Made more general by Clausius, it is now known as the Clausius-Clapeyron formula. It provided the basis of the second law of thermodynamics. In engineering, Clayeyron designed and built locomotives and metal bridges. He also served on a committee investigating the construction of the Suez Canal and on a committee which considered how steam engines could be used in the navy.*TIS

1842 Nicolas Camille Flammarion (26 Feb 1842; 3 Jun 1925 at age 83) was a French astronomer who studied double and multiple stars, the moon and Mars. He is best known as the author of popular, lavishly illustrated, books on astronomy, including Popular Astronomy (1880) and The Atmosphere (1871). In 1873, Flammarion (wrongly) attributed the red color of Mars to vegetation when he wrote “May we attribute to the color of the herbage and plants which no doubt clothe the plains of Mars, the characteristic hue of that planet...” He supported the idea of canals on Mars, and intelligent life, perhaps more advanced than earth's. Flammarion reported changes in one of the craters of the moon, which he attributed to growth of vegetation. He also wrote novels, and late in life he turned to psychic research. *TIS

1843 Karl Friedrich Geiser (26 Feb 1843 in Langenthal, Bern, Switzerland, 7 May 1934 in Küsnacht, Zürich, Switzerland) Swiss mathematician who worked in algebraic geometry and minimal sufaces. He organised the first International Mathematical Congress in Zurich.*SAU

1864 John Evershed (26 Feb 1864, 17 Nov 1956) English astronomer who discovered (1909) the Evershed effect - the horizontal motion of gases outward from the centres of sunspots. While photographing solar prominences and sunspot spectra, he noticed that many of the Fraunhofer lines in the sunspot spectra were shifted to the red. By showing that these were Doppler shifts, he proved the motion of the source gases. This discovery came to be known as the Evershed effect. He also gave his name to a spectroheliograph, the Evershed spectroscope.*TIS

DEATHS
1638 Claude-Gaspar Bachet de M´eziriac (9 Oct 1581, 26 Feb 1638), noted for his work in number theory and mathematical recreations. He published the Greek text of Diophantus’s Arithmetica in 1621. He asked the ﬁrst ferrying problem: Three jealous husbands and their wives wish to cross a river in a boat that will only hold two persons, in such a manner as to never leave a woman in the company of a man unless her husband is present. (With four couples this is impossible.)*VFR (I admit that I don't know how this differs from the similar river crossings problems of Alcuin in the 800's, Help someone?)His books on mathematical puzzles formed the basis for almost all later books on mathematical recreations.*SAU

1693 Sir Charles Scarborough MP FRS FRCP (19 December 1615 – 26 February 1693) was an English physician and mathematician.
He was born in St. Martin's-in-the-Fields, London in 1615, the son of Edmund Scarburgh, and was sent to St. Paul's School, whence he proceeded to Caius College, Cambridge, and educated at St Paul's School, Gonville and Caius College, Cambridge (BA, 1637, MA, 1640) and Merton College, Oxford (MD, 1646). While at Oxford he was a student of William Harvey, and the two would become close friends. Scarborough was also tutor to Christopher Wren, who was for a time his assistant.
Following the Restoration in 1660, Scarborough was appointed physician to Charles II, who knighted him in 1669; Scarborough attended the king on his deathbed, and was later physician to James II and William and Mary. During the reign of James II, Scarborough served (from 1685 to 1687) as Member of Parliament for Camelford in Cornwall.
Scarborough was an original fellow of the Royal Society and a fellow of the Royal College of Physicians, author of a treatise on anatomy, Syllabus Musculorum, which was used for many years as a textbook, and a translator and commentator of the first six books of Euclid's Elements (published in 1705). He also was the subject of a poem by Abraham Cowley, An Ode to Dr Scarborough.
Scarborough died in London in 1693. He was buried at Cranford, Middlesex, where there is a monument to him in the parish church erected by his widow. *Wik

1878 Pietro Angelo Secchi (18 Jun 1818, 26 Feb 1878 at age 59) Italian Jesuit priest and astrophysicist, who made the first survey of the spectra of over 4000 stars and suggested that stars be classified according to their spectral type. He studied the planets, especially Jupiter, which he discovered was composed of gasses. Secchi studied the dark lines which join the two hemispheres of Mars; he called them canals as if they where the works of living beings. (These studies were later continued by Schiaparelli.) Beyond astronomy, his interests ranged from archaeology to geodesy, from geophysics to meteorology. He also invented a meteorograph, an automated device for recording barometric pressure, temperature, wind direction and velocity, and rainfall.*TIS

1985 Tjalling Charles Koopmans (August 28, 1910 – February 26, 1985) was the joint winner, with Leonid Kantorovich, of the 1975 Nobel Memorial Prize in Economic Sciences. Koopmans' early works on the Hartree–Fock theory are associated with the Koopmans' theorem, which is very well known in quantum chemistry. Koopmans was awarded his Nobel prize (jointly with Leonid Kantorovich) for his contributions to the field of resource allocation, specifically the theory of optimal use of resources. The work for which the prize was awarded focused on activity analysis, the study of interactions between the inputs and outputs of production, and their relationship to economic efficiency and prices.*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