## Sidereus Nuncius *Wik |

~Simon Newcomb,

The 72nd day of the year; 72 is a pronic, heteromecic, or oblong number (and sometimes pronic is spelled promic). They are numbers that are the product of two consecutive integers

Oblong numbers have the property that if they are used in infinite nested radicals, they produce an integer, \(\sqrt(72+\sqrt(72+\sqrt(72+...))) = 9 \)

72 is the smallest number whose fifth power is the sum of five smaller fifth powers: \(19^5 + 43^5 + 46^5 + 47^5 + 67^5 = 72^5\).

The rule of 72 was once a commonly used approximation in banking and finance for the time it took an investment to double at r%. For a 5% investment, the approximate period would be 72/5 = 14.4 years. The rule applies to compound interest. The rule is based on an approximation of ln(2) = .693..

The Rhombicuboctahedron or Great Rhombicuboctahedron is an Archimedian solid that has 72 edges. It has 12 faces that are squares, 8 faces that are hexagons, and six faces that are octagons, for a total of 26 faces in all. Knowing the number of edges and faces, good students can calculate the number of vertices using Euler's Gem. (there is a lesser Rhombicuboctahedron or just Cubicuboctahedron which is a faceted version of the greater)

EVENTS

Thony Christie sent this translation from page 33 of the same book, "Written in Padua on the fourth day before the Ides of March 1610. Your Highnesses's most loyal servant, Galileo Galilei."

1615 Castelli reported to Galileo that the Archbishop of Pisa had demanded he relinquish the letter Galileo had sent him which were the foundation of a heresy charge to the church office by Nicolo Lorini. Galileo had tried to influence Cardinal Ballarmine with a modification of the original he had sent via Peiro Dini in February. *Brody & Brody, The Science Class You Wish You Had

1763 Jerome Lelande records a visit with Jean-Charles Borda in Dunkirk while on his way to visit England. "Mr Borda, came to dine with me at Mr Tully’s, the Irish doctor in Dunkirk, who told me he had very carefully observed the relationship of the moon with diseases.

From the top of the tower in Dunkirk you can see the Thames. There is a telescope at the top.

Mr Borda experiments on the resistance of air and water. He found it as the square of the speed, but not as the square of the sine of the angle of incidence; this varies a lot according to the shape of the bodies. (in 1762 he showed that a spherical projectile experiences only half the air a resistance of a cylindrical object of the same diameter.) *Richard Watkins

1883 Professor George Chrystal gave an address on "Present Fields of Mathematical Research" to the first regular meeting of hte Edinburgh Mathematical Society. *Proceedings of the Edinburgh Mathematical Society, Volumes 1-4

**1891**The journal, Nature, published what must have been one of it's most unusual articles. It was an unsolicited letter from a German hausfrau Miss Agnes Pockels to John William Strutt, aka Lord Rayleigh.

Miss Pockels wrote:

My lord,The letter went on to describe many of the results of Strutt's own experiments, and described results and conjectures even beyond his, all done in her own kitchen.

Will you kindly excuse my venturing to trouble you with a German letter on a scientific subject? Having heard of the fruitful researches carried on by you last year on the hitherto little understood properties of water surfaces, I thought it might interest you to know of my own observations on the subject For various reasons I am not in a position to publish them in scientific periodicals, and I therefore adopt this means of communicating to you the most important of them. First, I will describe a simple method, which I have employed for several years, for increasing or diminishing the surface of a liquid in any proportion, by which its purity may be altered at pleasure. … …

Lord Rayleigh demonstrated the integrity he was known for, by translating the letter into English, and sending it to the journal Nature, requesting it be printed without correction.

The story, with some additional detail about curiosity with his urine stream and its relation to the discovery of ink-jet printing can be found in Len Fisher's blog here. *Len Fisher

Despite her lack of formal training, Pockels was able to measure the surface tension of water by devising an apparatus known as the Pockels trough, a key instrument in the new discipline of surface science. Using an improved version of this slide trough, American chemist Irving Langmuir made additional discoveries on the properties of surface molecules, which earned him a Nobel Prize in chemistry in 1932. She published a number of papers and eventually received recognition as a pioneer in the new field of surface science. In 1931, together with Henri Devaux, Pockels received the Laura Leonard award from the Colloid Society. In the following year, the Braunschweig University of Technology granted her an honorary PhD. Pockels died in 1935 in Brunswick, Germany. She never married.*Wik

**1926**John von Neumann, 22, received his doctorate summa cum laude in mathematics with minors in experimental physics and chemistry from the University of Budapest. *Goldstein, The Computer form Pascal to von Neumann, p. 170

1997 Fairchild Semiconductor Sold: National Semiconductor Corp. completes the sale of its Fairchild Semiconductor business. Many consider Fairchild the "original" Silicon Valley company for its profound and diverse institutional legacy: a survey of over 100 large silicon valley companies in the 1980s found that almost all of them had links to Fairchild, mostly through ex-Fairchild employees who had spun off and started these companies on their own. Fairchild had been founded by Robert Noyce, Gordon Moore and six others who left en masse from Shockley Semiconductor, after that firm's founder and co-inventor of the transistor, William Shockley, struggled with a confrontational management style. Noyce and Moore later co-founded Intel Corporation. *CHM

2009 The U.S. House of Representatives passed a non-binding resolution (HRES 224), recognizing March 14, 2009, as National Pi Day .

In 1988 The earliest known official or large-scale celebration of Pi Day was organized by Larry Shaw in 1988 at the San Francisco Exploratorium, where Shaw worked as a physicist, with staff and public marching around one of its circular spaces, then consuming fruit pies. The Exploratorium continues to hold Pi Day celebrations.*Wik

BIRTHS

1683 John Theophile Desaguliers (12 Mar 1683, 29 Feb 1744 at age 60)French-English chaplain and physicist who studied at Oxford, became experimental assistant to Sir Isaac Newton. As curator at the Royal Society, his experimental lectures in mechanical philosophy and electricity (advocating, substantiating and popularizing the work of Isaac Newton) attracted a wide audience (*In his lectures Newton, it is said, often spoke only to the walls.*). In electricity, he coined the terms conductor and insulator. He repeated and extended the work of Stephen Gray in electricity. He proposed a scheme for heating vessels such as salt-boilers by steam instead of fire. He made inventions of his own, such as a planetarium, and improvements to machines, such as Thomas Savery's steam engine (by adding a safety valve, and using an internal water jet to condense the steam in the displacement chambers) and a ventilator at the House of Commons. He was a prolific author and translator. *TIS

1685 Bishop George Berkeley (12 March 1685 in Kilkenny, County Kilkenny, Ireland

- 14 Jan 1753 in Oxford, England). In 1734 he published The Analyst, Or a Discourse Addressed to an Inﬁdel Mathematician (namely, Edmund Halley). This work was a strong and reasonably justiﬁed attack on the foundation of the diﬀerential calculus. He called differentials “the ghosts of departed quantities.” *VFR

1824 Gustav Robert Kirchhoff (12 Mar 1824, 17 Oct 1887) German physicist who, with Robert Bunsen, established the theory of spectrum analysis (a technique for chemical analysis by analyzing the light emitted by a heated material), which Kirchhoff applied to determine the composition of the Sun. He found that when light passes through a gas, the gas absorbs those wavelengths that it would emit if heated, which explained the numerous dark lines (Fraunhofer lines) in the Sun's spectrum. In his Kirchhoff's laws (1845) he generalized the equations describing current flow to the case of electrical conductors in three dimensions, extending Ohm's law to calculation of the currents, voltages, and resistances of electrical networks. He demonstrated that current flows in a zero-resistance conductor at the speed of light. *TIS

1835 Simon Newcomb (12 Mar 1835; died 11 Jul 1909 at age 74) Canadian-American astronomer and and mathematician who prepared ephemerides (tables of computed places of celestial bodies over a period of time) and tables of astronomical constants. He was an astronomer (1861-77) before becoming Superintendent of the U.S. Nautical Almanac Office (1877-97). During this time he undertook numerous studies in celestial mechanics. His central goal was to place planetary and satellite motions on a completely uniform system, thereby raising solar system studies and the theory of gravitation to a new level. He largely accomplished this goal with the adoption of his new system of astronomical constants at the end of the century. *TIS This astonomer and mathematician

was the most honored scientist of his time. *VFR

Newcomb is buried in Arlington National Cemetery

Newcomb is often quoted as saying that heavier than air flight was impossible from a statement he made only two months before the Wright Brothers flight at Kitty Hawk, N.C.

"The mathematician of today admits that he can neither square the circle, duplicate the cube or trisect the angle. May not our mechanicians, in like manner, be ultimately forced to admit that aerial flight is one of that great class of problems with which men can never cope… I do not claim that this is a necessary conclusion from any past experience. But I do think that success must await progress of a different kind from that of invention." He also is famously quoted for saying, "We are probably nearing the limit of all we can know about astronomy."

1859 Ernesto Cesaro (12 March 1859 , 12 Sept 1906) died of injuries sustained while aiding a drowning youth. In addition to differential geometry Cesàro worked on many topics such as number theory where, in addition to the topics we mentioned above, he studied the distribution of primes trying to improve on results obtained in this area by Chebyshev. He also contributed to the study of divergent series, a topic which interested him early in his career, and we should note that in his work on mathematical physics he was a staunch follower of Maxwell. This helped to spread Maxwell's ideas to the Continent which was important since, although it it hard to realise this now, it took a long time for scientists to realize the importance of his theories.

Cesàro's interest in mathematical physics is also evident in two very successful calculus texts which he wrote. He then went on to write further texts on mathematical physics, completing one on elasticity. Two further works, one on the mathematical theory of heat and the other on hydrodynamics, were in preparation at the time of his death.

Cesàro died in tragic circumstances. His seventeen year old son went swimming in the sea near Torre Annunziata and got into difficulties in rough water. Cesàro went to rescue his son but sustained injuries which led to his death. *SAU

1925 Leo Esaki (12 Mar 1925, )Japanese physicist who shared (with Ivar Giaever and Brian Josephson) the Nobel Prize in Physics (1973) in recognition of his pioneering work on electron tunneling in solids. From some deceptively simple experiments published in 1958, he was able to lay bare the tunneling processes in solids, a phenomena which had been clouded by questions for decades. Tunneling is a quantum mechanical effect in which an electron passes through a potential barrier even though classical theory predicted that it could not. Dr. Esaki's discovery led to the creation of the Esaki diode, an important component of solid state physics with practical applications in high-speed circuits found in computers and communications networks.*TIS

1945 Vijay Kumar Patodi (March 12, 1945 – December 21, 1976) was an Indian mathematician who made fundamental contributions to differential geometry and topology. He was the first mathematician to apply heat equation methods to the proof of the Index Theorem for elliptic operators.[citation needed] He was a professor at Tata Institute of Fundamental Research, Mumbai (Bombay). *Wik

DEATHS

1834 Karl Wilhelm Feuerbach (30 May 1800 in Jena, Germany - 12 March 1834 in Erlangen, Germany) His mathematical fame rests entirely on three papers. Most important was this contribution to Euclidean geometry: The circle which passes through the feet of the altitudes of a triangle touches all four of the circles which are tangent to the three sides; it is internally tangent to the inscribed circle and externally tangent to each of the circles which touches the sides of the triangle externally. *VFR

The circle is also commonly called the Nine-point circle. It passes through the feet of the altitudes, the midpoints of the three sides, and the point half way between the orthocenter and the vertices.

Feuerbach did undertake further mathematical research. He sent a note from Ansbach to the journal Isis (dated 22 October 1826) entitled Einleitung zu dem Werke Analysis der dreyeckigen Pyramide durch die Methode der Coordinaten und Projectionen. Ein Beytrag zu der analytischen Geometrie von Dr. Karl Wilhelm Feuerbach, Prof. d. Math. (Introduction to the analysis of the triangular pyramid, by means of the methods of coordinates and projections. A study in analytic geometry by Dr Karl Wilhelm Feuerbach, Professor of Mathematics). This note announced results which were to appear in full in a later publication and indeed they did in a 48-page booklet Grundriss zu analytischen Untersuchungen der dreyeckigen Pyramide (Foundations of the analytic theory of the triangular pyramid) published in 1827. This is a second major work by Feuerbach and it has been studied carefully by Moritz Cantor who discovered that in it Feuerbach introduces homogeneous coordinates. He must therefore be considered as the joint inventor of homogeneous coordinates since Möbius, in his work Der barycentrische Calcul also published in 1827, introduced homogeneous coordinates into analytic geometry.*SAU

Although he is credited for its discovery, Karl Wilhelm Feuerbach did not entirely discover the nine-point circle, but rather the six point circle, recognizing the significance of the midpoints of the three sides of the triangle and the feet of the altitudes of that triangle. (See Fig. 1, points D, E, F, G, H, and I.) (At a slightly earlier date, Charles Brianchon and Jean-Victor Poncelet had stated and proven the same theorem.) But soon after Feuerbach, mathematician Olry Terquem himself proved the existence of the circle. He was the first to recognize the added significance of the three midpoints between the triangle's vertices and the orthocenter.*Wik

**1898 Johann Jakob Balmer**(1 May 1825, 12 Mar 1898 at age 72) Swiss mathematician and physicist who discovered a formula basic to the development of atomic theory. Although a mathematics lecturer all his life, Balmer's most important work was on spectral series by giving a formula relating the wavelengths of the spectral lines of the hydrogen atom (1885) at age 60. Balmer's famous formula is λ= hm

^{2}/(m

^{2}-n

^{2}). Wavelengths are accurately given using h = 3.6456 x10-7m, n = 2, and m = 3, 4, 5, 6, 7. He suggested that giving n other small integer values would give other series of wavelengths for hydrogen. Why this prediction agreed with observation was not understood until after his death when the theoretical work of Niels Bohr was published in 1913. *TIS

**1905**

**William Allen Whitworth**(1 February 1840 – 12 March 1905) was an English mathematician and a priest in the Church of England.

As an undergraduate, Whitworth became the founding editor in chief of the Messenger of Mathematics, and he continued as its editor until 1880. He published works about the logarithmic spiral and about trilinear coordinates, but his most famous mathematical publication is the book Choice and Chance: An Elementary Treatise on Permutations, Combinations, and Probability (first published in 1867 and extended over several later editions). The first edition of the book treated the subject primarily from the point of view of arithmetic calculations, but had an appendix on algebra, and was based on lectures he had given at Queen's College. Later editions added material on enumerative combinatorics (the numbers of ways of arranging items into groups with various constraints), derangements, frequentist probability, life expectancy, and the fairness of bets, among other topics.

Among the other contributions in this book, Whitworth was the first to use ordered Bell numbers to count the number of weak orderings of a set, in the 1886 edition. These numbers had been studied earlier by Arthur Cayley, but for a different problem. He was the first to publish Bertrand's ballot theorem, in 1878; the theorem is misnamed after Joseph Louis François Bertrand, who rediscovered the same result in 1887. He is the inventor of the E[X] notation for the expected value of a random variable X, still commonly in use, and he coined the name "subfactorial" for the number of derangements of n items.

Another of Whitworth's contributions, in geometry, concerns equable shapes, shapes whose area has the same numerical value (with a different set of units) as their perimeter. As Whitworth showed with D. Biddle in 1904, there are exactly five equable triangles with integer sides: the two right triangles with side lengths (5,12,13) and (6,8,10), and the three triangles with side lengths (6,25,29), (7,15,20), and (9,10,17). *Wik

**1915 Arthur Edwin Haynes**,(May 23, 1849;Baldwinsville, Onondaga County, New York, USA - Mar. 12, 1915; Minneapolis, Minnesota) Professor of Mathematics and Physics at Hillsdale College from 1875 until 1890. He came to Michigan in June 1858. They located near the village of Reading in southwestern Hillsdale Co. where the father had a farm.

Arthur received a common school education and remained on the family farm until he reached twenty years of age.

In the fall of 1870, Arthur entered Hillsdale College where he remained, a diligent student, until he was graduated from that institution in June 1875. He taught several terms of district school before graduation and was also employed during his college course as a tutor in mathematics in the college. During the summer between his junior and senior years, he assisted in the erection of the Central College building, in order to earn money to continue his studies. He carried a hod from the first story until the completion of the fourth, shouldering 80 pounds of brick and walking from the bottom to the top of the ladder (20 feet) without touching the hod handle, a feat that he was justly proud of. His classroom at Hillsdale was in that same building.

Immediately following graduation,he married and was appointed instructor in mathematics in Hillsdale College in the fall of 1875, and two years later was elected to the full Professorship. In 1885 he was elected a member of the London Mathematical Society. In 1890 he switched to the University of Minnesota. He wrote a paper on "The Mounting and Use of a Spherical Blackboard." He died in Minneapolis in 1915 and his body was removed back to Hillsdale where he was buried in Oak Grove Cemetary *PB notes

1946 Leonida Tonelli (19 April 1885 – 12 March 1946) was an Italian mathematician, most noted for creating Tonelli's theorem, usually considered a forerunner to Fubini's theorem. (A result which gives conditions under which it is possible to compute a double integral using iterated integrals. As a consequence it allows the order of integration to be changed in iterated integrals.)*Wik He published 137 papers, all single authored except one in 1915 written in collaboration with Guido Fubini, and a number of important books including Fondamenti di calcolo delle variazioni (2 volumes) (1921, 1923), Serie trigonometriche (1928), and (with E Lindner) Corso di matematica per la Scuola media (3 volumes) (1941, 1942).*SAU

1972 Louis Joel Mordell (28 January 1888 – 12 March 1972) was a U.S. born British mathematician, known for pioneering research in number theory. He was born in Philadelphia, USA, in a Jewish family of Lithuanian extraction. He came in 1906 to Cambridge to take the scholarship examination for entrance to St John's College, and was successful in gaining a place and support.

Having taken third place in the Mathematical Tripos, he began independent research into particular diophantine equations: the question of integer points on the cubic curve, and special case of what is now called a Thue equation, the Mordell equation

y

^{2}= x

^{2}+ k.

During World War I he was involved in war work, but also produced one of his major results, proving in 1917 the multiplicative property of Ramanujan's tau-function. The proof was by means, in effect, of the Hecke operators, which had not yet been named after Erich Hecke; it was, in retrospect, one of the major advances in modular form theory, beyond its status as an odd corner of the theory of special functions.

In 1920 he took a teaching position in Manchester College of Technology, becoming the Fielden Reader in Pure Mathematics at the Victoria University of Manchester in 1922 and Professor in 1923. There he developed a third area of interest within number theory, geometry of numbers. His basic work on Mordell's theorem is from 1921/2, as is the formulation of the Mordell conjecture.

In 1945 he returned to Cambridge as a Fellow of St. John's, when elected to the Sadleirian Chair, and became Head of Department. He officially retired in 1953. It was at this time that he had his only formal research students, of whom J. W. S. Cassels was one. His idea of supervising research was said to involve the suggestion that a proof of the transcendence of the Euler–Mascheroni constant was probably worth a doctorate. *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