## Monday 31 July 2023

### On This Day in Math - July 31

I advise my students to listen carefully the moment
they decide to take no more mathematics courses.
They might be able to hear the sound of closing doors.

~Caballero, James

The 212th day of the year; Besides being the Fahrenheit boiling point of water at sea level, 212 produces a prime of the form k10+k9+...+k2+k+1, when k=212. Edward Shore@edward_shore sent me a note:" That number would be 184,251,916,841,751,188,170,917.")
(students might explore different values of k, and different maximum exponents to produce primes..ie when k is 2, then 26 +25+...+22+2+1 is prime

The smallest even three-digit integer, abc, such that (abc)/(a*b*c) is also prime. [ie 212/(2*1*2)= 53 ]*Prime Curios

212 is a palindrome whose square is also a palindrome, 2122= 44944. It is the last year date for which this is true. It is also a palindrome in base 3(21212) with a copy of it's base 10 representation.

And I just learned from @fermatslibrary that 212 is in a palindromic approximation for π

666/212 = 3.141509... good for four decimal places.

EVENTS

1669 Lucasian professor Isaac Barrow sent John Collins a manuscript of Newton’s De analysi and thereby Newton’s anonymity began to dissolve. It was a summary of Newton’s work on the calculus and was written after Newton saw Nicholas Mercator’s Logarithmotechnia (1668).

$ln(1+x) = x -\frac{x^2}{2} + \frac{x^3}{3} -\frac{x^4}{4}+\cdots$

Newton wrote his paper in order that he would not lose credit for his work on inﬁnite series. Collins immediately recognized Newton’s genius. Although not published until 1711, this paper led to Newton’s appointment as Lucasian professor on 29 October 1669.*VFR

1730 Goldbach proves that Fermat numbers are pairwise coprime. (Fermat had said that the he thought the numbers of the form $2^{2^n} +1$ were all prime, although he could not prove it. The first five are (n=0...4) but Euler would prove the n=5 case was not prime by factoring it. No more primes have been found after n=4, but there is no proof there can not be more. I think this story, and Goldbach's discovery, make an interesting approach to proving the primes are infinite.) He claims that 1 is the only square among the triangular numbers *Euler Goldbach Correspondence

1744   Euler to Goldbach , "All around here chess is played passionately." He then mentions a certain strong local player he had been taking lessons from, then adds, "I am winning most games with him."  Master of us all in more ways than I knew.  *S. Strogatz

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1790 The U.S. Patent Office issued its ﬁrst patent to Samuel Hopkins of Vermont for his “process for making pot and pearl ashes,” whatever they are. Since George Washington and Thomas Jefferson signed Hopkins’ patent, more than 4 million have been issued. *VFR In 1790, the first U.S. patent was granted to Samuel Hopkins of Vermont for a process for making potash and pearl ashes. Potash was important as an ingredient in soap and fertilizer. The patent was granted for a term of 14 years and signed by President George Washington, who had the previous month signed the first U.S. patent statute into law on 10 April 1790. Hopkins did not get Patent with a serial No.1 as thousands of patents were issued before the Patent Office began to number them. Congress had passed the Patent Act on 10 Apr 1790. Two other patents were granted that year - one for a new candle-making process and the other the flour-milling machinery of Oliver Evans. The next year, 1791, Samuel Hopkins also was granted the first Canadian patent.*TIS
 *C. Pickover

1851 Gauss witnessed the opening ceremonies when the newly constructed railway from Cassel reached Gottingen. *VFR

1943 Ireland issued—as its ﬁrst stamp with a mathematical theme—two stamps to celebrate the centenary of the discovery of Quaternions by Sir William Rowan Hamilton. [Scott #126-7]. *VFR

1990The U.S. government panel approved the use of gene therapy to treat human disease. Gene therapy uses DNA to treat disease, usually by replacing a faulty gene with a healthy copy. Recent clinical studies suggest this technique holds promise for the future treatment of Parkinson’s disease. *.rsc.org

2015 The second full moon this month (the other was on the 2nd). This only happens “Once in a blue moon”—and this is the origin of the phrase. Consequently, there were be thirteen full moons this year.  The last "blue moon" was in 1985, and the next is predicted in 2018.
The next blue moon takes place on 31 August 2023. As this Moon is also a supermoon, it will be a Super Blue Moon.
Supermoon: A Full or New Moon that occurs when the center of the Moon is less than 360,000 kilometers (ca. 223,694 miles) from the center of Earth.

 *Farmer's Almanac

BIRTHS

1704 Gabriel Cramer (31 July 1704 – 4 January 1752). He is best known for “Cramer’s Rule,” a method for solving systems of simultaneous linear equations using determinants. *VFR Gabriel Cramer (31 July 1704 – 4 January 1752) was a Swiss mathematician, born in Geneva. He showed promise in mathematics from an early age. At 18 he received his doctorate and at 20 he was co-chair of mathematics. In 1728 he proposed a solution to the St. Petersburg Paradox that came very close to the concept of expected utility theory given ten years later by Daniel Bernoulli. He published his best known work in his forties. This was his treatise on algebraic curves, "Introduction à l'analyse des lignes courbes algébriques", published in 1750. It contains the earliest demonstration that a curve of the n-th degree is determined by n(n + 3)/2 points on it, in general position. He edited the works of the two elder Bernoullis; and wrote on the physical cause of the spheroidal shape of the planets and the motion of their apsides (1730), and on Newton's treatment of cubic curves (1746). He was professor at Geneva, and died at Bagnols-sur-Cèze.*Wik

 *Geeks For Geeks

1712 Samuel König (July 31, 1712, Büdingen – August 21, 1757, Zuilenstein near Amerongen) was a German mathematician who is best remembered for his part in a dispute with Maupertuis over the Principle of Least Action.*SAU

1718 John Canton (31 July 1718 – 22 March 1772) British physicist and teacher, born Stroud, Gloucestershire. He made a number of minor discoveries in physics and chemistry. As a result of preparing artificial magnets in 1749 he was elected to the Royal Society. In 1762, he demonstrated that water was slightly compressible. He invented a number of devices in connection with electricity. His notable work, between 1756 and 1759, was to record that on days when the aurora borealis was particularly bright, a compass needle behaved with more irregularity than usual. Thus he was the first to record this as an electromagnetic phenomenon for what is now known to be a magnetic storm.*TIS
==========================================================
1790 The U.S. Patent Office issued its first patent to Samuel Hopkins of Vermont for his “process
for making pot and pearl ashes,” whatever they are. Since George Washington and Thomas
Jefferson signed Hopkins’ patent, more than 4 million have been issued. *VFR
Hopkins was a Philadelphia Quaker who later moved to New Jersey. He was living in Philadelphia when the patent was granted. The patent was signed by President Washington, Attorney General Randolph and Secretary of State Jefferson. The original document is in the collections of the Chicago Historical Society.

Potash was America’s first industrial chemical. It is an impure form of potassium carbonate mixed with other potassium salts. Until the 1860s it was solely derived from the ashes of hardwood trees and certain other plants. Potash was a leading industrial alkali from antiquity until the close of the nineteenth century, when it was finally abandoned for most uses in favor of soda (sodium carbonate). It was essential for making soap and glass, dyeing fabrics, baking, and making saltpeter for gunpowder. Today it is principal ingredient in fertilizers. *SUITER SWANTZ

1826 Daniel Friedrich Ernst Meisse mathematical work covers number theory, work on Möbius inversion and the theory of partitions as well as work on Bessel functions, asymptotic analysis, refraction of light and the three body problem. *SAU

1843 Friedrich Robert Helmert (July 31, 1843 – June 15, 1917) German geodesist and an important writer on the theory of errors.
From 1887 Helmert was professor of advanced geodesy at the University of Berlin and director of the Geodetic Institute.
Helmert received many honours. He was president of the global geodetic association of "Internationale Erdmessung", member of the Prussian Academy of Sciences in Berlin, was elected a member of the Royal Swedish Academy of Sciences in 1905, and recipient of some 25 German and foreign decorations. *TIA

1858 Richard Dixon Oldham (31 July 1858 – 15 July 1936) Irish geologist and seismologist who discovered evidence for the existence of the Earth's liquid core (1906). In studying seismograms of great 1897 Indian Earthquake he identified P (primary) and S (secondary) waves. It is interesting that he did not get a clue to the presence of the core from the S waves, which are actually incapable of being transmitted through the liquid of the outer core. (The liquid core does not transmit the shear wave energy released during an earthquake.) Rather he noted the existence of a shadow zone in which P waves from an earthquake in the opposite hemisphere of the earth failed to appear*TIS

1863 George Abram Miller (31 July 1863 – 10 February 1951) was an early group theorist whose many papers and texts were considered important by his contemporaries, but are now mostly considered only of historical importance.
Miller was born in Lynnville, Lehigh County, Pennsylvania, and died in Urbana, Illinois.*Wik

1923 Joseph B. Keller (born July 31, 1923, Paterson, New Jersey) is an American mathematician who specializes in applied mathematics. He is best known for his work on the "Geometrical Theory of Diffraction" (GTD).
He worked on the application of mathematics to problems in science and engineering, such as wave propagation. He contributed to the Einstein-Brillouin-Keller method for computing eigenvalues in quantum mechanical systems.
In 1988 he was awarded the U.S. National Medal of Science, and in 1997 he was awarded the Wolf Prize by the Israel-based Wolf Foundation. In 1996, he was awarded the Nemmers Prize in Mathematics.*Wik

1927 F. E. Browder born. Worked in Nonlinear monotone operators and convex sets in Banach spaces. and more.

1943 Ireland issued—as its first stamp with a mathematical theme—two stamps to celebrate the centenary of the discovery of Quaternions by Sir William Rowan Hamilton. [Scott #126-7].*VFR

------------------------------------------------------------------------------------------------------------------
1945 John O'Connor (31st July 1945 in Luton, Bedfordshire, England.- )
Lists his Research interests A lapsed topologist, I am interested in Computational Algebra.
I am interested in the History of Mathematics and at present am supervising two research students in this area. * His Personal web page

DEATHS

1726 Nikolaus II Bernoulli died (February 6, 1695, Basel, Switzerland – July 31, 1726, St. Petersburg, Russia). *VFR Nicolaus(II) Bernoulli was the favourite of three sons of Johann Bernoulli. He made important mathematical contributions to the problem of trajectories while working on the mathematical arguments behind the dispute between Newton and Leibniz.*SAU

1784 Denis Diderot died. (October 5, 1713 – July 31, 1784) was a French philosopher, art critic, and writer. He was a prominent persona during the Enlightenment and is best-known for serving as co-founder and chief editor of and contributor to the Encyclopédie. *Wik

1896 Ludwig Christian Wiener (7 December 1826 Darmstadt – 31 July 1896 Karlsruhe) was a German mathematician, physicist and philosopher, known for his explanation of Brownian motion , which identified him as a skillful experimenter. He mainly dealt with geometry.*Wik

1913 John Milne (30 December 1850 – 31 July 1913) English seismologist who invented the horizontal pendulum seismograph (1894) and was one of the European scientists that helped organize the seismic survey of Japan in the last half of the 1800's. Milne conducted experiments on the propagation of elastic waves from artificial sources, and building construction. He spent 20 years in Japan, until 1895, when a fire destroyed his property, and he returned home to the Isle of Wight. He set up a new laboratory and persuaded the Royal Society to fund initially 20 earthquake observatories around the world, equipped with his seismographs. By 1900, Milne seismographs were established on all of the inhabited continents and he was recognized as the world's leading seismologist. He died of Bright's disease*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 30 July 2023

### On This Day in Math - July 30

I have created a new universe from nothing.

~Janos Bolyai

The 211th Day of the Year
The 211th day of the year; 211 is a primorial prime,(a prime that is one more, or one less than a primorial  can you find the next larger (or smaller) primorial prime?

211 is also the sum of three consecutive primes (67 + 71 + 73)...

There are 211 primes on a 24-hour digital clock. (00:00 - 23:59) *Derek Orr @ Derektionary

211 is the 4th** Euclid number: 1 + product of the first n primes.(after Euclid's method of proving the primes are infinite. most Euclid numbers, unlike 211, are not themselves prime, but are divisible by a prime different than any of the primes in the product n#) (**some would call it the fifth since Euclid seemed to consider 1 as a unit as similar to the primes.)

211 is a prime lucky number, and there are 211 lucky primes less than 10^4 (or 10 ^(2+1+1))*Prime Curios

211 is the concatenation of the smallest one digit prime and the smallest two digit prime, 2, 11.

211 = 3^5 - 2^5, two consecutive fifth powers, it is only the second, following 31, and is the last year date with the property.

Hardy wrote a New Year Resolution in a card to Ramujan to get 211, none out, in a cricket test match at the oval.

A Lazy Caterer number, A Pizza can be cut into 211 pieces with 20 straight cuts.

211 is a repunit in base 14 (111)14^2 + 14 + 1

211 is also SMTP status code for system status.*Wik

211 is an odd number, so it is the difference of two consecutive squares, 106^2 - 105^2 = 211

211 is the first of fifteen consecutive odd numbers that sum to the cube of 15, 3375

211 is a prime of the form 4k+3. According to Gauss' reciprocity law, if two numbers, p and q are in this sequence then there exists a solution to only one of x^2 = p (mod q) or x^2 = q (mod p). 3 is another number in the sequence. Can you find an x^2 so that one of these congruences is true?

And one more from *Prime Curios. If you've ever heard the expression "a month of Sundays," for something that takes a really long time that's 31 Sundays, starting on a Sunday and going for 30 more weeks to end on a Sunday, or 211 days, Sunday to Sunday.

EVENTS

1738 Euler sends a letter to John Bernoulli with the solution to a question from Danial Bernoulli regarding isoperimetric curves, particularly the  one for which the integral of rm gave a maximum or minimum.

1859 Bernhard Reimann is appointed full professor at Gottingen, succeeding his two former teachers, Gauss and Dirichlet. He also is allowed to occupy Gauss' apartments at the observatory. *John Derbyshire, Prime Obsession, pg 135

In 1898, Corn Flakes were invented by William Kellogg. At Battle Creek Sanitarium, Sanitarium superintendent, Dr. John Harvey Kellogg and Will Keith Kellogg, his younger brother and business manager, invented many grain-based foods, including a coffee substitute, a type of granola, and peanut butter to provide patients a strict nutritious diet. In 1894 they unintentionally invented a flaked cereal process based on wheat. By 1898, W.K. Kellogg had developed the first flaked corn cereal. Patients enjoyed the cereals and wanted more to take home. In 1906, the Battle Creek Toaster Corn Flake Company was founded by W.K. Kellogg.*TIS

1907 The Axiom of Choice is usually given as created by Zermelo in 1908, presumably because that was the year it appeared in Mathematische Annalen, but the date on the actual paper is "Chesières, 30 July 1907.". The paper contains, "AXIOM VI. (Axiom of choice). If T is a set whose elements all are sets that are different from 0 and mutually disjoint, its union "union of T" includes at least one subset S1 having one and only one element in common with each element of T." [The original German read "Axiom der Auswahl".]
Ernst Zermelo used the Axiom of Choice to prove that every set can be well-ordered on a paper of 1904, but did not use the name "Axiom of Choice". *Jeff Miler, Earliest Known Uses of Some of the Words of Mathematics

1918 Richard Courant sat down with Ferdinand Springer and signed a contract for the series of books now famous as the “Yellow Series.” *Constance Reid, Courant in Gottingen and New York, p. 72

1971 Apollo 15 mission became the fourth mission to land on the moon when the Falcon lunar lander touched down. This mission allowed the astronauts to spend more time on the surface of the moon. The lander stayed three days on the surface and the crew conducted over 18 hours of outside work. They also were aided for the first time by a lunar rover vehicle.*Science Today

1983 The Sumida River Festival in Tokyo celebrated its 250th anniversary, as the oldest, grandest fireworks festival in Japan. The festival spent $400,000 on the hanabi—literally “fire flowers”— alone: 17,500 shells in an hour and 20 minutes, none bigger than four-and-a-half inches in diameter. How many shells is that per minute? [New York Times, July 17, 1983, sect. 10, p. 37] Every last Saturday in July, colorful fireworks are launched from both sides of the Sumida River. The spectacle is best seen from close to the river, although it can get very crowded, and best spots are often taken hours in advance. Still, the festive atmosphere, with people dressing up in yukata and picnicking in the streets and parks, is worth it. =========================================================== 1985 Julia Robinson died of leukemia. After receiving her Ph.D. in 1948 under the direction of Alfred Tarski, she began work on Hilbert’s tenth problem, the problem which occupied most of her professional life. Robinson was awarded a doctorate in 1948 and that same year started work on Hilbert's Tenth Problem: find an effective way to determine whether a Diophantine equation is soluble. Along with Martin Davis and Hilary Putman she gave a fundamental result which contributed to the solution to Hilbert's Tenth Problem, making what became known as the Robinson hypothesis. She also did important work on that problem with Matijasevic after he gave the complete solution in 1970. *SAU BIRTHS 1857 Thorstein Bunde Veblen, (July 30, 1857 – August 3, 1929) was an American economist and sociologist, and a leader of the so-called institutional economics movement. Besides his technical work he was a popular and witty critic of capitalism, as shown by his best known book The Theory of the Leisure Class (1899). 1863 Henry Ford (July 30, 1863 – April 7, 1947) American inventor and car manufacturer, born in Dearborn, Mich. Ford first experimented with internal combustion engines while he was an engineer with the Edison Illuminating Company. He completed his first useful gas motor on 24 Dec 1893. The Quadricycle, he designed made its first road test on 4 Jun 1896. In 1903 the Ford Motor Company was incorporated. By 1908, Ford was manufacturing the low cost, reliable Model T, while continuing to revolutionize his industry. Ford introduced precision manufactured parts designed to be standardized and interchangeable parts. In 1913, production was increased using a continuous moving assembly line. By 1918, half of all cars in America were Model T's.*TIS 1878 Joel Stebbins (July 30, 1878 – March 16, 1966) was an American astronomer who pioneered photoelectric photometry in astronomy. He earned his Ph.D at the University of California. He was director of University of Illinois observatory from 1903 to 1922 and the Washburn Observatory at the University of Wisconsin-Madison from 1922 to 1948. After 1948, Stebbins continued his research at Lick Observatory until his final retirement in 1958. Stebbins brought photoelectric photometry from its infancy in the early 1900s to a mature technique by the 1950s, when it succeeded photography as the primary method of photometry. Stebbins used the new technique to investigate eclipsing binaries, the reddening of starlight by interstellar dust, colors of galaxies, and variable stars. Stebbins received the following awards: Rumford Prize of the American Academy of Arts and Sciences (1913) Henry Draper Medal of the National Academy of Sciences (1915) Bruce Medal of the Astronomical Society of the Pacific (1941) Gold Medal of the Royal Astronomical Society (1950) Henry Norris Russell Lectureship of the American Astronomical Society (1956) The Lunar crater Stebbins and the asteroid 2300 Stebbins are named in his honor. *TIA 1887 Felix Andries Vening Meinesz (The Hague July 30, 1887 - Amersfoort August 10, 1966) was a Dutch geophysicist and geodesist who was known for his measurements of gravity at sea for which he devised the Vening Meinesz pendulum apparatus with comparable accuracy as on land. Starting in 1923 he conducted several global gravity surveys on voyages on submarines, particularly to and in the Indonesian Archipelago. He detected strong gravity anomaly belts running parallel to the Indonesian deep sea trenches. He explained these Meinesz belts as sites of downbuckling of the Earth's crust. He introduced the concept of regional isostasy taking flexure of an elastic crust into account. He also contributed to physical geodesy: The Vening Meinesz formula connects the deviation of the vertical from the plumbline to gravity anomalies. *TIS 1888 Vladimir Zworykin (July 29 [O.S. July 17] 1888 – July 29, 1982) was born in Russia. After emigrating to Pittsburgh, Zworykin took a job at Westinghouse Electric Corp., where in 1923 he filed a patent for the iconoscope, the first television transmission tube and a technology that was to become of interest to early computer designers. With a later invention, the kinescope, Zworykin was able to create the first all-electric television system. Zworykin took the technology to RCA in 1929, where he continued his work and earned the title "father of television.*CMH DEATHS 1762 William Braikenridge (1700; 30 July 1762 in London, England) was an English clergyman who worked on geometry and discovered independently many of the same results as Maclaurin.*SAU 1832 French chemist John Antoine Chaptal He authored the first book on industrial chemistry, and coined the name "nitrogen". Chaptal also helped improve the technology used to manufacture sulfuric acid, saltpetre for gunpowder, beetroot sugar and wine, amongst other things. *RSC.Org 1978 Rufus Bowen (23 February 1947 - 30 July 1978) worked on dynamical systems. Rufus died of a cerebral hemorrhage at the age of 31. *SAU In 1970, Bowen completed his doctorate in Mathematics at Berkeley under Stephen Smale, and joined the faculty as assistant professor in that year. At this time he began calling himself Rufus, the nickname he had been given because of his red hair and beard. He was an invited speaker at the 1974 International Mathematical Conference in Vancouver, British Columbia.He was promoted to full professorship in 1977. Bowen's mature work dealt with dynamical systems theory, a field which Smale, Bowen's dissertation advisor, explored and broadened in the 1960s. 1985 Julia Robinson (December 8, 1919 – July 30, 1985) died of leukemia. After receiving her Ph.D. in 1948 under the direction of Alfred Tarski, she began work on Hilbert’s tenth problem, the problem which occupied most of her professional life.*VFR She also worked on computability, decision problems and non-standard models of arithmetic. *SAU Her sister was Constance Reid who wrote biographies of several mathematicians and several popular math books. Julia Robinson's Job Description: Monday: Try to prove theorem Tuesday: Try to prove theorem Wednesday: Try to prove theorem Thursday: Try to prove theorem Friday: Theorem false Elizabeth Scott in a tribute to Robinson, 2002 Dr. Lyle B. Borst, (Nov 24, 1912 - July 30, 2002) was a nuclear physicist who helped build Brookhaven National Laboratory's nuclear reactor and was an early member of the Manhattan Project. In 1950, Dr. Borst led the construction of the Brookhaven Graphite Research Reactor, which was the largest and most powerful reactor in the country and the first to be built solely for research and other peacetime uses of atomic energy. Within the first nine months of operating the reactor, Dr. Borst announced that it had produced a new type of radioactive iodine, which is used in treating thyroid cancer. In 1952, based on studies of new types of atomic nuclei created in the reactor, Dr. Borst helped explain the mystery behind giant stars, known as supernovae, that burst with the energy of billions of atomic bombs and flare for several years with the brilliance of several million suns. Dr. Borst found that beryllium 7, an isotope of beryllium that does not occur naturally on earth, is formed in supernovae by the fusion of two helium nuclei. The fusion takes place after the star has used up its hydrogen supply. This reaction absorbs huge quantities of energy, causing the star to collapse in the greatest cosmic explosion known. *NY Times obit. 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 29 July 2023 ### On This Day in Math - July 29 To call in the statistician after the experiment is done may be no more than asking him to perform a postmortem examination: he may be able to say what the experiment died of. ~Ronald Fisher The 210th Day of the Year 210 is the last year day that is a Primorial, 210 = 7# = 7*5*3*2. The name "primorial", coined by Harvey Dubner, draws an analogy to primes similar to the way the name "factorial" relates to factors.*Wikipedia Of course that means it is the smallest number that is the product of four distinct primes, and the only such year date. 210 is a Harshad (joy-giver) number, divisible by the sum of its digits. In fact, it is a multiple Harshad number since 210/3 = 70, which is also a Harshad number. (21, 20, 29) and (35, 12, 37) are the two least primitive Pythagorean triangles with different hypotenuses and the same area (=210). Students are challenged to find another pair of such PPTs There are an infinite number of numbers that appear six or more times in Pascal's Arithmetic Triangle, but only three of them; 1, 120, and 210 are year dates. 7! hours is 210 days. The Combination of ten things taken four at a time is 210. It is also C(21,2) 13 + 17 + 19 + 23 + 29 + 31 + 37 + 41 = 210, the sum of eight consecutive primes 210 is the 20th Triangular number, the sum of the integers from 1 - 20. 210 is the last year date which is both a triangular number and the product of consecutive numbers, 14 x 15. It is also the last to be the product of three consecutive numbers, 5 x 6 X 7. Three different ways to make a 3x3 magic square with a magic constant of 210, Take the classic 3x3 and multiply each term by 14, 56 126 28 42 70 98 112 14 84 Or with consecutive integers starting at 76 69 74 67 68 70 72 73 66 71 Or maybe with increments of five 65 90 55 60 70 80 85 50 75 The magic is in the middle, all else stems from there. 210 in binary is a balanced number, with the same numbers of ones and zeros, and reading from left to right the zeros never outnumber the ones. The sum of the squares of the divisors of 12, is 210. EVENTS 1654 Pascal wrote a letter to Fermat agreeing to a result of Fermat on a probability problem about repeated rolls of a single die for a wager. "Impatience has seized me as well as it has you, and although I am still abed, I cannot refrain from telling you that I received your letter in regard to the problem of the points yesterday evening from the hands of M. Carcavi, and that I admire it more than I can tell you. I do not have the leisure to write at length, but, in a word, you have found the two divisions of the points and of the dice with perfect justice. I am thoroughly satisfied as I can no longer doubt that I was wrong, seeing the admirable accord in which I find myself with you." *York Univ Hist of Stats 1698 In a letter to John Bernoulli, Leibniz introduces the dot for multiplication..(cajori 233; vol 1 pg 267) “The dot was introduced as a symbol for multiplication by G. W. Leibniz. On July 29, 1698, he wrote in a letter to John Bernoulli: “I do not like X as a symbol for multiplication, as it is easily confounded with x; … often I simply relate two quantities by an interposed dot and indicate multiplication by ZC · LM. Hence, in designating ratio I use not one point but two points, which I use at the same time for division.” Cajori shows the symbol as a raised dot. However, according to Margherita Barile, consulting Gerhardt's edition of Leibniz's Mathematische Schriften (G. Olms, 1971), the dot is never raised, but is located at the bottom of the line. She writes that the non-raised dot as a symbol for multiplication appears in all the letters of 1698, and earlier, and, according to the same edition, it already appears in a letter by Johann Bernoulli to Leibniz dated September, 2nd 1694. The dot was used earlier by Thomas Harriot (1560-1621) in Analyticae Praxis ad Aequationes Algebraicas Resolvendas, which was published posthumously in 1631, and by Thomas Gibson in 1655 in Syntaxis mathematica. However Cajori says, "it is doubtful whether Harriot or Gibson meant these dots for multiplication. They are introduced without explanation. It is much more probable that these dots, which were placed after numerical coefficients, are survivals of the dots habitually used in old manuscripts and in early printed books to separate or mark off numbers appearing in the running text" (Cajori vol. 1, page 268). However, Scott (page 128) writes that Harriot was "in the habit of using the dot to denote multiplication." And Eves (page 231) writes, "Although Harriot on occasion used the dot for multiplication, this symbol was not prominently used until Leibniz adopted it." The colon (:) was used in 1633 in a text entitled Johnson Arithmetik; In two Bookes (2nd ed.: London, 1633). However Johnson only used the symbol to indicate fractions (for example three-fourths was written 3:4); he did not use the symbol for division "dissociated from the idea of a fraction" (Cajori vol. 1, page 276). Gottfried Wilhelm Leibniz (1646-1716) used : for both ratio and division in 1684 in the Acta eruditorum . Blue - decimal point, Lt Gr - comma, Dk Green - both, Red - Arabic decimal separator, Gray - no data  *Wik 1739 D’Alembert, age 21, submitted his ﬁrst mathematical paper to the Academy of Sciences. *VFR As his knowledge of mathematics was mainly due to self-study, he often found that others had already established his mathematical discoveries by more elegant and more direct means. In 1739 d’Alembert submitted his first paper to the French Académie Royale des Sciences, in which he described the errors found in the standard textbook, Analyse démontrée, written by Charles Reyneau. *webpage of Robert Nowland 1773 First schoolhouse West of the Alleghenies.*VFR (built in Schoenbrunn, OH.) The first schoolhouse west of the Alleghenies was built by a band of Moravian missionaries that had come to Ohio to establish a community to minister to the Lenape (Delaware) Indians. The band was led by David Zeisberger who believed everyone had the right to an education. He translated the Bible in the Lenape language and opened the Christian school to teach white and native children alike. School was taught in German, the Moravian native language, and the Lenape languague. In colonial times, most schools did not teach boys and girls together. Girls from prosperious families went to seperate schools that taught home-making skills. Public schools didn't allow girls to attend. Puritans believed in teaching girls how to read so they could learn Scripture, but that was as far as their formal education would get. Educated girls were considered to not be suitable wives. Schools where blacks and native Americans attended with white children were unheard of although there were some Quaker and missionary schools that taught black and native Americans. The Schoenbrunn School bucked all of these colonial traditions. In Moravian schools, blacks, native Americans, and girls were taught together with white boys. The Moravians believed that all children should receive an education so they could study the Bible and minister to others. Schoenbrunn School was one of the first public schools in the United States to do this.  HHHistory.com On this day in 1808, François Arago *escaped* from prison in Mallorca where he had been imprisoned as a spy, and started his journey back to France carrying his logbook of measurements of the meridian. After some misadventures he reached France 11 months later. On 3 September 1806 Arago and Biot set out for Spain. They continued the task which Méchain had been undertaking on his final expedition and by 1808 they were on Mallorca, an important point which allowed the Paris meridian to be continued south of Barcelona. They had been operating in Spain at an extremely difficult time, given that they were French. Napoleon had turned his attention towards Spain and Portugal in 1807 and marched his armies through Spain to Portugal in October 1807. They conquered Portugal and occupied parts of Spain. In May 1808 Napoleon declared his brother Joseph Bonaparte as Spanish ruler and the War of Independence began. Biot and Arago must have looked extremely suspicious; two Frenchmen with sophisticated measuring instruments working on Spanish territory. Biot fled back to France but Arago remained on Mallorca, disguised as a Spaniard, trying to complete his measurements which he had recorded in a logbook. However lighting of fires on the top of Mount Galatzo was pretty suspicious so he was arrested as a spy and put in prison. Arago managed to persuade the commander of the prison that he was a scientist, not a spy, and the commander agreed to give Arago a chance to escape. He did so on 29 July 1808 and, still carrying his precious logbook, managed to find a fishing boat heading for Algiers, which he boarded. Reaching Algiers on 3 August he went to the French consul who supplied him with a forged Austrian passport and by 16 August he was on a boat heading to Marseille. This might have been a remarkable adventure had it ended at that point, but more drama was to come. The boat on which Arago was sailing was captured while on its way to France by a Spanish warship and he was back in captivity again. Arago was held in a Spanish prison in Roses but after only a short spell the Spanish decided to send their prisoners to Palamos since the French armies were advancing through Spain. However Arago was lucky and, having been recognized by the authorities, was released an put on another boat for Marseille on 28 November. It was not to be, however, for again Arago failed to reach his homeland. A storm blew the boat back to Bougie on the north African coast where he was captured by Muslims. After further adventures during which he persuaded his captors that he wished to convert to Islam to obtain favorable treatment, he was allowed to return to Algiers which he did overland, arriving there on 25 December. A new local leader in Algiers was opposed to the French and Arago found himself in prison waiting to be shipped off to a penal colony. However the French consul again came to his rescue and, on 21 June 1809, Arago was put, for the third time, on a ship bound for Marseille. This time he reached his destination without mishap and on 2 July 1809 he was standing on French soil.  Arago's grave in the Père Lachaise cemetery in Paris *SAU 1867 Thomas Hill, president of Harvard College, who was also somewhat of a mathematician, wrote Benjamin Peirce, who was a professor there: “I have the honor of informing you that the University, on Commencement Day, conferred on you the Degree of Doctor of Laws in recognition of the transcendent ability with which you have pursued mathematical physical investigations, and in particular for the luster which she has herself for so many years borrowed from your genius.” [P. 10 of Benjamin Peirce, AMM offprint, 1925] *VFR 1878 This was the height of search for the intra-Mercurial planet Vulcan using eclipses to block the Sun. (Vulcan was a small planet proposed to exist in an orbit between Mercury and the Sun. In an attempt to explain peculiarities of Mercury's orbit, in the 19th-century French mathematician Urbain Jean Joseph Le Verrier hypothesized that they were the result of another planet, which he named Vulcan.) Several observers claim sightings, but they are never confirmed. The problem is finally resolved by Albert Einstein (1879-1955) in his general theory of relativity in 1916. *NSEC  Vulcan in a lithographic map from 1846 *Wik 1958 President Eisenhower signed the National Aeronautics and Space Act. NASA opened for business on 1 October 1958, and within a week launched Project Mercury—the start of the U.S. manned space program. *VFR 2005, another candidate for tenth planet was announced by Mike Brown of California Institute of Technology. Its diameter is estimated at 2,100 miles - about 1-1/2 times that of Pluto. Its orbit is eccentric and inclined at about 45 degrees to the main plane of the solar system. It was named 2003 UB313 on a photograph made 31 Oct 2003. Later, its motion was recognized, on 8 Jan 2005. With orbits significantly inclined to the others, the status as a planet of either or even Pluto, is a subject for debate. They are in a region of numerous frozen comet-like objects beyond Neptune - the Kuiper Belt. The object Sedna - somewhat smaller than Pluto - was also found there in 2004. NASA also in an official statement referred to 2003 UB313 as a tenth planet*TIS 2015 On July 29, 2015, a 15th type of pentagon that would tile the plane was announced by Casey Mann, Jennifer McLoud, and David Von Derau of the University of Washington Bothell. In 1918, K. Reinhardt discovered five different families of convex pentagons that could tile the plane. This was the complete list until 1968, when Richard Kershner wrote about three more families of tiling pentagons. Martin Gardner wrote about the complete list of eight tiling pentagons in 1975, and then got a message from Richard James III about another type. Martin updated the readers of Mathematical Games, but then got a message from a housewife with no mathematical training, Marjorie Rice, who found four more families of tiling pentagons. In 1985, Rolf Stein found a convex pentagon that can tile the plane. Now, there is one more. *Wolfram  *guardian.com BIRTHS 1858 Francesco Gerbaldi (29 July 1858, La Spezia, Italy to 29 June 1934, Pavia, Italy) was an Italian geometer, who proved Gerbaldi's theorem. In geometry, Gerbaldi's theorem, proved by Gerbaldi (1882), states that one can find six pairwise apolar linearly independent nondegenerate ternary quadratic forms. These are permuted by the Valentiner group. (say that three times real fast) *Wik 1862 Eduard Brückner (July 29, 1862–May 20, 1927) pioneer climate researcher. He also studied the glaciers of the Alps and particularly the effect of the ice ages on the Earth's surface features. By analyzing direct and indirect observations of climatic fluctuations, he discovered the 35-year Brückner climatic cycle (1887) of swings between damp-cold and warm-dry conditions. He initiated scientific debate on whether climate change should be interpreted as a natural function of the Earth system, or whether it was influenced by man's activities, such as deforestation. He considered the impact of climate change on the balance of power between nations and its economic significance in agricultural productivity, emigration, river transportation and the spreading of diseases.*TIS 1898 Isidor Isaac Rabi (29 July 1898 – 11 January 1988) was an American physicist who was awarded the Nobel Prize for Physics in 1944 for his invention (in 1937) of the atomic and molecular beam magnetic resonance method of measuring magnetic properties of atoms, molecules, and atomic nuclei. He spent most of his life at Columbia University (1929-67), where he performed most of his pioneering research in radar and the magnetic moment associated with electron spin in the 1930s and 1940s. His Nobel-winning work led to the invention of the laser, the atomic clock, and diagnostic uses of nuclear magnetic resonance. He originated the idea for the CERN nuclear research center in Geneva (founded 1954). *TIS Three Nobel Prize winners in 1962: John Bardeen, Isidor Rabi, and Werner Heisenberg (left to right); the occasion is unknown (Wikimedia commons 1912 Noel Bryan Slater, often cited NB Slater, (1912 in Blackburn , January 31 1973) was a British mathematician and physicist who worked on including statistical mechanics and physical chemistry, and probability theory.*Wik DEATHS 1781 Johann Kies (September 14, 1713—July 29, 1781) a German astronomer and mathematician. Born in Tübingen, Kies worked in Berlin in 1751 alongside Jérôme Lalande in order to make observations on the lunar parallax in concert with those of Nicolas Louis de Lacaille at the Cape of Good Hope. From 1742 to 1754, at the recommendation of the mathematician Leonhard Euler, he was made professor of mathematics at Berlin's Academy of Sciences and astronomer at its observatory. He subsequently taught also at the Collegium of Tübingen. From 1754 to 1755, Kies served as director of the Astronomisches Rechen-Institut in Heidelberg. Kies was one of the first to propagate Newton's discoveries in Germany, and dedicated two of his works to the Englishman: De viribus centralibus (Tübingen, 1758) and De lege gravitatis (Tübingen, 1773). Kies is also the author of a work on lunar influences: De influxu lunae in partes terrae mobiles (Tübingen, 1769). He wrote many other works, both in French and in Latin, on astronomy. Kies corresponded with Euler from 1747 to 1767. Their correspondence consists of 8 letters, all of which were written by Kies. The crater Kies on the Moon is named in his honor. *TIA 1839 Gaspard de Prony. (July 22, 1755 - July 29, 1839) Cauchy was elected his successor at the Bureau des Longitudes but was not admitted as he refused to take the oath of allegiance. *VFR In 1793, de Prony began a major task of producing logarithmic and trigonometric tables for the French Cadastre. The effort was begun at the request of the French National Assembly, which, after the French Revolution wanted to bring uniformity to the multiple measurements and standards used throughout the nation. The tables and their production were vast, with values calculated to between fourteen and twenty-nine decimal places. Inspired by Adam Smith's Wealth of Nations, de Prony divided up the labor, bragging that he "could manufacture logarithms as easily as one manufactures pins." At the top of the organizational hierarchy were scientists and mathematicians who devised the formulas. Next were workers who created the instructions for doing the calculations. At the bottom were about ninety "computers" (as they were called) who were not trained in mathematics, but who followed the instructions." One of de Prony's important scientific inventions was the 'de Prony brake' which he invented in 1821 to measure the performance of machines and engines. He also was first to propose using a reversible pendulum to measure gravity, which was independently invented in 1817 by Henry Kater and became known as the Kater's pendulum. He also created a method of converting sinusoidal and exponential curves into a systems of linear equations. Prony estimation is used extensively in signal processing and finite element modelling of non linear materials. Prony was a member, and eventually president, of the French Academy of Science. He was also elected a foreign member of the Royal Swedish Academy of Sciences in 1810. His name is one of the 72 names inscribed on the Eiffel Tower. *Wik 1898 John Alexander Reina Newlands, (July 22, 1755 - July 29, 1839) was a British chemist who first established an order of elements by the atomic weights, and observed a periodicity in the properties. Every eighth element has similar properties, hence he named the Law of Octaves (7 Feb 1863). It took another quarter century, and the work of others, such as Mendeleev, for the significance of his discovery to be recognized. He died in London.*TIS 1944 David Eugene Smith (January 21, 1860 in Cortland, New York – July 29, 1944 in New York) died in New York City at the age of eighty-four.*VFR Smith attended Syracuse University, graduating in 1881 (Ph. D., 1887; LL.D., 1905). He studied to be a lawyer concentrating in arts and humanities, but accepted an instructorship in mathematics at the Cortland Normal School in 1884. He also knew Latin, Greek, and Hebrew. He became a professor at the Michigan State Normal College in 1891, the principal at the State Normal School in Brockport, New York (1898), and a professor of mathematics at Teachers College, Columbia University (1901). Smith became president of the Mathematical Association of America in 1920. He also wrote a large number of publications of various types. He was editor of the Bulletin of the American Mathematical Society; contributed to other mathematical journals; published a series of textbooks; translated Klein's Famous Problems of Geometry, Fink's History of Mathematics, and the Treviso Arithmetic. He edited Augustus De Morgan's Budget of Paradoxes (1915) and wrote many books on Mathematics. *Wik 1962 Ronald Aylmer Fisher FRS (17 February 1890 – 29 July 1962) was an English statistician, evolutionary biologist, eugenicist and geneticist. Among other things, Fisher is well known for his contributions to statistics by creating Fisher's exact test and Fisher's equation. Anders Hald called him "a genius who almost single-handedly created the foundations for modern statistical science" while Richard Dawkins called him "the greatest of Darwin's successors". In 2010 Dawkins named him "the greatest biologist since Darwin". Fisher was opposed to the conclusions of Richard Doll and A.B. Hill that smoking caused lung cancer. He compared the correlations in their papers to a correlation between the import of apples and the rise of divorce in order to show that correlation does not imply causation. To quote Yates and Mather, "It has been suggested that the fact that Fisher was employed as consultant by the tobacco firms in this controversy casts doubt on the value of his arguments. This is to misjudge the man. He was not above accepting financial reward for his labours, but the reason for his interest was undoubtedly his dislike and mistrust of puritanical tendencies of all kinds; and perhaps also the personal solace he had always found in tobacco." After retiring from Cambridge University in 1957 he spent some time as a senior research fellow at the CSIRO in Adelaide, Australia. He died of colon cancer there in 1962. He was awarded the Linnean Society of London's prestigious Darwin–Wallace Medal in 1958. Fisher's important contributions to both genetics and statistics are emphasized by the remark of L.J. Savage, "I occasionally meet geneticists who ask me whether it is true that the great geneticist R.A. Fisher was also an important statistician"*Wik The stained glass window is from the Greatroom at Caius College. 1994 Dorothy Mary Hodgkin OM FRS (12 May 1910 – 29 July 1994), known professionally as Dorothy Crowfoot Hodgkin or simply Dorothy Hodgkin, was a British biochemist who developed protein crystallography, for which she won the Nobel Prize in Chemistry in 1964. She advanced the technique of X-ray crystallography, a method used to determine the three-dimensional structures of biomolecules. Among her most influential discoveries are the confirmation of the structure of penicillin that Ernst Boris Chain and Edward Abraham had previously surmised, and then the structure of vitamin B12, for which she became the third woman to win the Nobel Prize in Chemistry. In 1969, after 35 years of work and five years after winning the Nobel Prize, Hodgkin was able to decipher the structure of insulin. X-ray crystallography became a widely used tool and was critical in later determining the structures of many biological molecules where knowledge of structure is critical to an understanding of function. She is regarded as one of the pioneer scientists in the field of X-ray crystallography studies of biomolecules. *Wik 1996 Marcel-Paul "Marco" Schützenberger (October 24, 1920 – July 29, 1996) was a French mathematician and Doctor of Medicine. His work had impact across the fields of formal language, combinatorics, and information theory.[1] In addition to his formal results in mathematics, he was "deeply involved in [a] struggle against the votaries of Darwinism,"[2] a stance which has resulted in some mixed reactions from his peers and from critics of his stance on evolution. Several notable theorems and objects in mathematics bear his name (for example Schutzenberger group).*Wik 2004 Walter Feit (October 26, 1930 – July 29, 2004)was an Austrian mathematician who (with John Thompson) proved one of the most important theorems about finite simple groups.*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 ## Friday 28 July 2023 ### On This Day in Math - July 28 It appears to me that if one wishes to make progress in mathematics one should study the masters and not the pupils. Quoted in O Ore's, Niels Abel, Mathematician Extraordinary The 209th day of the year; 209=16+25+34+43+52+61. Also 209 is a "Self number" A self number, Colombian number or Devlali number (after the town where he lived) is an integer which, in a given base, cannot be generated by any other integer added to the sum of that other integer's digits. For example, 21 is not a self number, since it can be generated by the sum of 15 and the digits comprising 15, that is, 21 = 15 + 1 + 5. No such sum will generate the integer 209, hence it is a self number. These numbers were first described in 1949 by the Indian mathematician D. R. Kaprekar. students might want to explore self numbers for patterns [The earliest use of Colombian number I can find is by B. Recaman (1974). "Problem E2408". Amer. Math. Monthly 81. Would love to know if there are earlier uses.] 209 is the maximum number of pieces that can be made by cutting an annulus with 19 straight cuts. The curve 42x^2 - y^2 = 209 contains the 'prime points' (3, 13), (5, 29), (7, 43), and (13, 83). *Prime Curios There is an infinity of pairs x,y where x^2 - y^2 - xy = 209 for x, y integers *Prime Curios As far as I know, there are only two three digit numbers so that abc^2 = uvwxyz and uvw+xyz = abc. These are called three digit Kaprekar numbers. 209 is involved in each case. The two numbers are 297^2 = 88209, with 88 + 209 = 297 and 703^2 = 494209 where 494 + 209 = 703 See More Math Facts for every Year Day here EVENTS 1619 Kepler wrote Napier expressing his enthusiasm for Napier’s invention of logarithms. *VFR Napier who used logarithm tables extensively to compile his Ephemeris and therefore dedicated it to Napier, remarked: ... the accent in calculation led Justus Byrgius [Joost Bürgi] on the way to these very logarithms many years before Napier's system appeared; but ... instead of rearing up his child for the public benefit he deserted it in the birth. — Johannes Kepler, Rudolphine Tables (1627) 1851 First American eclipse expedition to Europe when George Phillips Bond (1825 - 1865) led a team to Scandinavia. *NSEC In the transcription of his notes he wrote: 1851 A total solar eclipse was photographed for the ﬁrst time. *VFR The first correctly-exposed photograph of the solar corona was made during the total phase of the solar eclipse of 28 July 1851 at Königsberg (now Kaliningrad) by a local daguerreotypist named Berkowski at the Royal Observatory in Königsberg, Prussia (now Kalinigrad in Russia). Berkowski, whose first name was never published, observed at the Royal Observatory. A small 6-cm refracting telescope was attached to the 15.8-cm Fraunhofer heliometer and a 84-second exposure was taken shortly after the beginning of totality. United Kingdom astronomers, Robert Grant and William Swan, and Austrian astronomer Karl Ludwig von Littrow observed this eclipse and determined that prominences are part of the Sun because the Moon is seen to cover and uncover them as it moves in front of the Sun.*Wik In 1858, fingerprints were used as a means of identification for the first time.*TIS The English first began using fingerprints in July of 1858, when Sir William James Herschel, Chief Magistrate of the Hooghly district in Jungipoor, India, first used fingerprints on native contracts. On a whim, and without thought toward personal identification, Herschel had Rajyadhar Konai, a local businessman, impress his hand print on a contract. The idea was merely "... to frighten [him] out of all thought of repudiating his signature." The native was suitably impressed, and Herschel made a habit of requiring palm prints--and later, simply the prints of the right Index and Middle fingers--on every contract made with the locals. Personal contact with the document, they believed, made the contract more binding than if they simply signed it. Thus, the first wide-scale, modern-day use of fingerprints was predicated, not upon scientific evidence, but upon superstitious beliefs. As his fingerprint collection grew, however, Herschel began to note that the inked impressions could, indeed, prove or disprove identity. While his experience with fingerprinting was admittedly limited, Sir William Herschel's private conviction that all fingerprints were unique to the individual, as well as permanent throughout that individual's life, inspired him to expand their use. *History of Fingerprints, Onin.com  *Wik I was reminded by Douglas W Boone that Mark Twain uses fingerprint identification in his book Pudd'nhead Wilson. "As we see most clearly in the trial scene at the end of the book, fingers turn out to be Tom's deadliest enemy when his fingerprints turn up on the murder weapon, revealing his identity. Referring to fingerprints, Pudd'nhead explains: Every human being carries with him from his cradle to his grave certain physical marks which do not change their character, and by which he can always be identified—and that without shade of doubt or question. " *SHMOOP 1866 The ﬁrst act (in the USA) legalizing the employment of the metric system was approved (14 Stat. L. 339). The act provided that it “shall be lawful throughout the United States of America to employ the weights and measures of the metric system.” *VFR 1882 The Institute of Accountants and Bookkeepers was organized in New York City. It was the first accounting society in the United States. *FFF 1899 Cantor asks Dedekind whether the set of all cardinal numbers is itself a set, because if it is it would have a cardinal number larger than any other cardinal. *VFR 1948 Allen Turing writes to Jack Good with an estimate of the number of neurons in the human brain. "I have repeatedly looked in books on neurology ... and never found any numbers offered. My own estimate is 3x108 to 3x109. " *Turing Archives 1984 The town of Eighty-four Pennsylvania celebrated it's centennial on this day. 1997 Dell Computer Corp. announced its entry into the workstation market with the Dell Workstation 400. The move to the more powerful desktop computers, most commonly used for engineering, followed Dell's entry into the network server industry as it expanded from personal desktop computers and laptops in order to grab a larger part of the market. Dell offered its workstations for$3,000 to \$8,000. (Yikes!!!) *CHM

 *CHM

2061 Halley's comet will next reach perihelion. The comet last reached perihelion on 9 February 1986, and will reach it again on 28 July 2061 *Wik

BIRTHS
1849 Robert Scott studied at Cambridge and was elected to a fellowship. After a short time teaching he studied to be a barrister. He spent most of his career as Bursar and Master of St John's College Cambridge. He published a book on Determinants. *SAU

1867 Charles Dillon Perrine (July 28, 1867; Steubenville, Ohio, – June 21, 1951) U.S. astronomer who discovered the sixth and seventh moons of Jupiter in 1904 and 1905, respectively. In 1904 he published a calculation of the solar parallax (a measure of the Earth-Sun distance) based on observations of the minor planet Eros during one of its close approaches to the Earth. *TIS

 maser components at amhistorymuseum HT toBen Gross ‏@bhgross144
1915 Charles Hard Townes (July 28, 1915 – January 27, 2015) was an American Nobel Prize-winning physicist and educator. Townes was known for his work on the theory and application of the maser, on which he got the fundamental patent, and other work in quantum electronics connected with both maser and laser devices. He shared the Nobel Prize in Physics in 1964 with Nikolay Basov and Alexander Prokhorov.
In a career that spanned six decades, Dr. Townes developed radar bombing systems and navigation devices during World War II, advised presidents and government commissions on lunar landings and the MX missile system, verified Einstein’s cosmological theories, discovered ammonia molecules at the center of the Milky Way, and created an atomic clock that measured time to within one second in 300 years. He died at the age of 99 in Berkeley, California*Wik *NY Times

1928 John Bell (28 June 1928 – 1 October 1990)   his great achievement was that during the 1960s he was able to breathe new and exciting life into the foundations of quantum theory, a topic seemingly exhausted by the outcome of the Bohr-Einstein debate thirty years earlier, and ignored by virtually all those who used quantum theory in the intervening period. Bell was able to show that discussion of such concepts as 'realism', 'determinism' and 'locality' could be sharpened into a rigorous mathematical statement, 'Bell's inequality', which is capable of experimental test. Such tests, steadily increasing in power and precision, have been carried out over the last thirty years. *SAU

1954 Gerd Faltings (July 28, 1954 - ) was born in Gelsenkirchen-Buer, West Germany. In 1986 he received a Fields Medal for solving Mordell’s Conjecture using arithmetic algebraic geometry. *VFR He has also been closely linked with the work leading to the final proof of Fermat's Last Theorem by Andrew Wiles. In 1983 Faltings proved that for every n greater than 2 there are at most a finite number of coprime integers x, y, z with xn + yn = zn. This was a major step but a proof that the finite number was 0 in all cases did not seem likely to follow by extending Falting's arguments.
However, Faltings was the natural person that Wiles turned to when he wanted an opinion on the correctness of his repair of his proof of Fermat's Last Theorem in 1994.*TIS

DEATHS

1818 Gaspard Monge (9 May 1746 – 28 July 1818) died in disgrace in Bourbon Paris, having been stripped of his place in the reorganized Acad´emie of 1816. Although he contributed to diﬀerential equations and the geom¬etry of surfaces, his special interest was descriptive geometry. Employed as a teacher, he made signiﬁcant contributions to educational reform. [Ivor Grattan-Guiness, Convolutions in French Mathematics, 1800–1840, p. 616]
On the fall of Napoleon he was deprived of all his honors, and even excluded from the list of members of the reconstituted Institute. Monge died at Paris on 28 July 1818 and was interred in Le Père Lachaise Cemetery, in Paris, in a mausoleum. He was later transferred to the Panthéon. The mausoleum and Monge's bust remain in Le Père Lachaise Cemetery.
A statue portraying him was erected in his home town of Beaune, Côte-d'Ors in 1849. His name is one of the 72 names inscribed on the Eiffel Tower.

1944 Sir Ralph Fowler (17 January 1889 – 28 July 1944) a brilliant physicist. But it may be for his influence upon others that he is best known. In fact, no less than fifteen Fellows of the Royal Society and three Nobel Laureates were supervised by Fowler between 1922 and 1939. The total number supervised during this time was a staggering sixty-four giving him an average of eleven research students at any given time. One might be led to believe that this did not allow for any depth of relationship to form between him and his students. However, this was far from the truth of the matter. Those who studied under Fowler had a tremendous admiration for him. In particular, E A Milne [1] was especially taken by the man whom he fondly referred to as "the kind of man you can still remain friendly with, even when he has sold you a motor-bike; it is not possible to say more" and whom he called a "prince amongst men".
Aside from Milne, on whom he had a profound impact, he also had the opportunity of influencing the likes of Sir Arthur Eddington, Subramanian Chandrasekhar, Paul Dirac, Sir William McCrea, Lady Jeffreys and others either directly through supervision or indirectly through collaboration. Even in his personal life he was intimately connected with brilliant people having married Eileen, the only daughter of Lord Rutherford whom he met through Rutherford's Cavendish Laboratory at Cambridge. Sometimes his influence was simply the fact that he was known to so many people. It was Fowler who ultimately introduced Paul Dirac to the burgeoning field of quantum theory in 1923 leading Dirac to the forefront of its ultimate discovery in 1925. Fowler also put Dirac and Werner Heisenberg in touch with each other through Niels Bohr. As Sir William McCrea simply put it: "he was the right man in the right place at the right time." *SAU
1968 Otto Hahn (8 Mar 1879; 28 Jul 1968 at age 89) German physical chemist who, with the radiochemist Fritz Strassmann, is credited with the discovery of nuclear fission. He was awarded the Nobel Prize for Chemistry in 1944 and shared the Enrico Fermi Award in 1966 with Strassmann and Lise Meitner. Element 105 carries the name hahnium in recognition of his work.*TIS

1968 Otto Hahn (8 Mar 1879; 28 Jul 1968 at age 89) German physical chemist who, with the radiochemist Fritz Strassmann, is credited with the discovery of nuclear fission. He was awarded the Nobel Prize for Chemistry in 1944 and shared the Enrico Fermi Award in 1966 with Strassmann and Lise Meitner. Element 105 carries the name hahnium in recognition of his work.*TIS

"For the rest of his life, Hahn provided a standard explanation: fission was a discovery that relied on chemistry only and took place after Meitner left Berlin; she and physics had nothing to do with it, except to prevent it from happening sooner." *Lise Meitner by  Ruth Lewin Sime

The prize-winning science-fiction writer, Frederik Pohl, talking about Szilard's epiphany in Chasing Science (pg 25), ".. we know the exact spot where Leo Szilard got the idea that led to the atomic bomb.  There isn't even a plaque to mark it, but it happened in 1938, while he was waiting for a traffic light to change on London's Southampton Row.  Szilard had been remembering H. G. Well's old science-fiction novel about atomic power, The World Set Free and had been reading about the nuclear-fission experiment of Otto Hahn and Lise Meitner, and the lightbulb went on over his head." (Maybe she had a little idea?)

in 1939 during the Fifth Washington Conference on Theoretical Physics at the George Washington University, Nobel Laureate Niels Bohr publicly announced the splitting of the uranium atom. The resulting “fission,” with its release of two hundred million electron volts of energy, heralded the beginning of the atomic age.

The announcement came just weeks after Otto Hahn and Fritz Strassmann, two of Bohr’s colleagues at Copenhagen, reported that they had discovered the element barium after bombarding uranium with neutrons. After receiving the news in a letter, physicist Lise Meitner and her cousin, Otto Frisch, correctly interpreted the results as evidence of nuclear fission. Frisch confirmed this experimentally on January 13, 1939. *atomicheritage.org

Niels Bohr was planning a trip to America to discuss other problems with Einstein who had found a haven at Princeton's Institute for Advanced Studies. Bohr came to America, but the principal item he discussed with Einstein was the report of Meitner and Frisch. Bohr arrived at Princeton on January 16, 1939. He talked to Einstein and J. A. Wheeler who had once been his student. From Princeton the news spread by word of mouth to neighboring physicists, including Enrico Fermi at Columbia. Fermi and his associates immediately began work to find the heavy pulse of ionization which could be expected from the fission and consequent release of energy. *Atomic Archive

2000 Abraham Pais (May 19, 1918 – July 28, 2000) Dutch-American physicist and science historian whose research became the building blocks of the theory of elemental particles. He wrote Subtle Is the Lord: The Science and Life of Albert Einstein, which is considered the definitive Einstein biography. In Holland, his Ph.D. in physics was awarded on 9 Jul 1941, five days before a Nazi deadline banning Jews from receiving degrees. Later, during WW II, while in hiding to evade the Gestapo, he worked out ideas in quantum electrodynamics that he later shared when working with Niels Bohr (Jan - Aug 1946). In Sep 1946, he went to the U.S. to work with Robert Oppenheimer at Princeton, where Pais contributed to the foundations of the modern theory of particle physics.*TIS

2004 Francis Harry Compton Crick (8 June 1916 – 28 July 2004) was a British biophysicist, who, with James Watson and Maurice Wilkins, received the 1962 Nobel Prize for Physiology or Medicine for their determination of the molecular structure of deoxyribonucleic acid (DNA), the chemical substance ultimately responsible for hereditary control of life functions. Crick and Watson began their collaboration in 1951, and published their paper on the double helix structure on 2 Apr 1953 in Nature. This accomplishment became a cornerstone of genetics and was widely regarded as one of the most important discoveries of 20th-century biology. *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