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| Duomo Santa Maria del Fiore, *Wik |
For since the fabric of the universe is most perfect and the work of a most wise creator, nothing at all takes place in the universe in which some rule of the maximum or minimum does not appear.
~Leonhard Euler
The 105th day of the year, Paul Erdős conjectured that this is the largest number n such that the positive values of n - 2k are all prime. *Prime Curios
105 is the first degree for which the cyclotomic polynomial factors are not all 1, 0 or -1.
105 is the sum of consecutive integers in seven distinct ways. 105 =
1 + 2 + 3 + … + 13 + 14 =
6 + 7 + 8 + … + 14 + 15 =
12 + 13 + … + 17 + 18 =
15 + 16 + 17 + 18 + 19 + 20 =
19 + 20 + 21 + 22 + 23 =
34 + 35 + 36 =
52 + 53
105 is the largest composite number for which all the odd numbers less than it either are prime, or share a factor with it.
The distinct prime factors of 105, (3,5,7) add up to 15. The same is true of the factors of 104, so they form a Ruth Aaron pair. Someone noticed the factor relation about these two shortly after Hank Aaron hit his 715th home run to break Ruth's record of 714 on April 8th, 1974. 104 and 105 form the fifth such pair in year days, and yet, there is only one more for the rest of the year.
As the sum of the first fourteen integers, 105 is a Triangular number.
105 is the middle number in a prime quadruplet (101, 103, 107, 109) all in the same decade of numbers so it is the only odd composite in that decade of numbers. 15 holds a similar position in the teens decade.
EVENTS
1566 Early Tycho Brahe in 1566 he left Denmark for the second time, and arrived at Wittenberg on the 15 th April. The University of Wittenberg had been founded in 1502, and had then for nearly fifty years been one of the most renowned in Europe. He Studied under Caspar Peucer, distinguished as a mathematician, a physician, and a historian. Tycho, however, did not profit very much from Peucer's instruction, as the plague broke out at Wittenberg, so that he was induced to leave it on the 16th September, after a stay of only five months. *TYCHO BRAHE, A PICTURE OF SCIENTIFIC LIFE AND WORK IN THE SIXTEENTH CENTURY BY J. L. E. DREYER
1726, writer William Stukeley held a conversation with Isaac Newton in Kensington during which Newton recalled “when formerly, the notion of gravitation came into his mind.” Later, Stukeley writing in his Memoirs of Sir Isaac Newton's Life, recorded that Newton said, “It was occasioned by the fall of an apple, as he sat in contemplative mood. Why should that apple always descend perpendicularly to the ground, thought he to himself. Why should it not go sideways or upwards, but constantly to the earth's centre.” *TIS The story was also related to John Conduitt who was Newton's assistant at the Royal mint, and the husband of Newton's niece. The idea that the apple hit Newton on the head seems to date from the early 20th Century. A copy of the page of Stukeley's manuscript where he tells this story is available on-line at the Royal Society.
1747 Euler, writing in response to a now lost letter from D'Alembert, that he opposed the suggestion that logarithms of negative numbers could exist and in particular that \(e^1\) could have both a positive and a negative value. He adds that as soon as the value of e, in \( y = e^x \) is defined, then the logarithm of all values are also assigned.
In the same letter he continues his argument by giving a new definition, now popular, of \( e^x\) as \(e^x = 1 + x + \frac{x^2}{1*2} \dots \) and hence the idea of a negative logarithm is impossible. *L E Dickson, History of the Exponential and Logarithmic Concept. Am Math Monthly Mar, 1913
1770, Dr. Joseph Priestley made the first mention in English that a piece of a rubber substance could erase marks from black-lead pencils. At the end of the Preface to his work, Familiar Introduction to the Theory and Practice of Perspective, he described it: "Since this Work was printed off, I have seen a substance excellently adapted to the purpose of wiping from paper the mark of a black-lead-pencil. It must, therefore, be of singular use to those who practice drawing. It is sold by Mr Nairne, Mathematical Instrument Maker, opposite the Royal Exchange. He sells a cubical piece of about half an inch for three shillings; and he says it will last several years." *TIS
It was not until 1770 that we found out that a natural rubber made from plants can be used as an eraser. That year, Edward Nairne, an English engineer, picked up a piece of rubber instead of breadcrumbs and discovered that rubber can erase pencil markings. Yes, you read that right, before gum rubber, the common pencil eraser was breadcrumbs.
Now, if only ..... Oh they did
In 1858 a Pencil with attached eraser patented. It has benefited generations of mathematics students. The first patent for attaching an eraser to a pencil was issued to a man from Philadelphia named Hyman Lipman. This patent was later held to be invalid because it was merely the combination of two things, without a new use.
1831 Gauss introduces the term "complex" for a+bi. Most of the 17th and 18th century writers spoke of a + bi as an imaginary quantity. Gauss saw the desirability of having different names for ai and a + bi, so he gave to the latter the Latin expression numeros integros complexos.
Gauss wrote:
...quando campus arithmeticae ad quantitates imaginarias extenditur, ita ut absque restrictione ipsius obiectum constituant numeri formae a + bi, denotantibus i pro more quantitatem imaginariam \/-1, atque a, b indefinite omnes numeros reales integros inter -oo et +oo. Tales numeros vocabimus numeros integros complexos, ita quidem, ut reales complexis non opponantur, sed tamquam species sub his contineri censeatur.
The citation above is from Gauss’s paper "Theoria Residuorum Biquadraticorum, Commentatio secunda," Societati Regiae Tradita, Apr. 15, 1831, published for the first time in Commentationes societatis regiae scientiarum Gottingensis recentiones, vol. VII, Gottingae, MDCCCXXXII (1832)]. [Julio González Cabillón]
The term complex number was used in English in 1856 by William Rowan Hamilton. The OED2 provides this citation: Notebook in Halberstam & Ingram Math. Papers Sir W. R. Hamilton (1967) III. 657: "a + ib is said to be a complex number, when a and b are integers, and i = [sqrt] -1; its norm is a^2 + b^2; and therefore the norm of a product is equal to the product of the norms of its factors."
*Jeff Miller, Earliest Known Uses of Some of the Words of Mathematics
1869 W.S. Gilman Jr (of the Naval Observatory, I think{help!}) to Prof Elias Loomis of Yale, sends an account of an Aurora viewed from Brooklyn, NY. He ranks the aurora "inferior in brightness to... one I Witnessed ... on 15th September" (1868) *American Journal of Science
1877, a steam-engine driven helicopter model built by Enrico Forlanini rose 40 ft (12 m). The machine weighed 3.5 kg (7.7 lbs). Its coaxial rotors were powered by a two-cylinder steam engine. Just before takeoff the spherical steam accumlator was charged with 10 atmospheres of pressure, enabling the craft to rise and remain aloft for 20 seconds. Forlanini (1848-1930) was an Italian pioneer of scientific aviation. He built a hydroplane, which could take off on water (1905) and a new type of semirigid aircraft in1914. He also invented the hydrofoil boat. Alexander Graham Bell secured the Italian's patents to pursue his own interest in hydrofoil development. TIS
In 1895, a mathematical relationship between the frequencies of the hydrogen light spectrum was reported by a Swiss school teacher, Johann Balmer, in Annalen der Physik. Its significance was overlooked until Niels Bohr realized this showed a structure of energy levels of the electron in the hydrogen atom. *TIS
1904 term "discrete mathematics was introduced in The Twelfth Annual Report of the Ohio State Academy of Science “The new mathematics...has triumphed for its own domain in cases where the continuity methods were wholly inapplicable, where arithmology, discrete mathematics was called for and victorious. *Jeff Miller, Earliest Known Uses of Some of the Words of Mathematics
In 1570 in Sir Henry Billingsley's translation of Euclid's Elements he described discrete numbers, but not a discrete mathematics : "Two contrary kynds of quantity; quantity discrete or number, and quantity continual or magnitude"
"Discrete Mathematics" is a biweekly peer-reviewed scientific journal in the broad area of discrete mathematics, combinatorics, graph theory, and their applications. It was established in 1971
The first modern Discrete Mathematics text, "Discrete Mathematics" by László Lovász, József Pelikán, and Katalin Vesztergombi, was published in 1975.
In 1912, the fourth dimension was spoken of by Albert Einstein as time. *TIS The great French mathematician d’Alembert, made the first published suggestion that time is the fourth dimension in his 1754 article on the dimensions of space in the Encyclopédie, edited by Diderot and himself. He attributed the idea there to “un homme d’esprit de ma connaissance,” who is thought to have been his fellow mathematician Lagrange, although the latter did not publish such a suggestion until 1797 in his Théorie des fonctions analytiques.
As well as discrediting Kant’s argument that space must be Euclidean, Poincaré declared that space need not even be three-dimensional. In an article in Nature, December, 1869,
Charles Howard Hinton (1853–1907) (Husband of Mary Boole, the daughter of George Boole) taught Uppingham School in Rutland, where Howard Candler, a friend of Edwin Abbott Abbott's, also taught.)
Rather than supporting scientists like Helmholtz who believed that the non-Euclidean geometries of Lobachevsky and Bolyai had discredited Kant’s contention that Euclidean geometry is true a priori, Hinton gave the philosopher credit for identifying space as the necessary means by which human beings cognise the world. However, instead of accepting the three-dimensionality of perception as an unalterable fact of life, Hinton proposed in his books A New Era of Thought (1888) and The Fourth Dimension (1904) that it was merely a temporary feature of man’s evolution. In 1888, Hinton coined the term Tesseract for a four dimensional cube. Earlier, W.I. Stringham had drawn and published in the American Journal of Mathematics an article containing one of the earliest known sets of illustrations of the projections on a plane of the six regular polyhedroids or polytopes — the four-dimensional counterparts of the five regular polyhedra: tetrahedron, octahedron, cube, icosahedron and dodecahedron.
Stringham's depiction of the four-dimensional cube, and current illustration of a tesseract
1952 The first bank credit card was issued by Franklin National Bank, Franklin Square, New York. Purchases were charged to the bank, which made the payments, and then billed the card holders. *FFF (Would love image of this if anyone has one?)
In 1966, the first X-ray three-dimensional stereo fluoroscopic system was installed for use in heart catherization by Richard J Kuhn. The $30,000 machine, developed by Joseph Quinn was put into use at the University of Oregon Medical Center, Portland, Oregon, U.S. The X-ray tube had one anode but two cathodes, an image intensifier with polarizers, and a synchronized analyzer. This produced a 3D image that could be seen through a viewing mirror without the use of special glasses. *TIS
Godfrey Hounsfield of EMI Laboratories created the first commercially available CT scanner in 1972. He co-invented the technology with physicist Dr. Allan Cormack and both researchers were later on jointly awarded the 1979 Nobel Prize in Physiology and Medicine.
The cross-sectional imaging, or “slices”, from CT scans made diagnosing health issues like heart disease, tumors, internal bleeding, and fractures simpler for doctors while also being easier on the patients. Through the following years, with how effective the CT scanners proved to be improvements on the design were quickly developed.
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| Allan Cormack |
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| Godfrey Hounsfield |
1977 First West Coast Computer Faire Begins:
The first West Coast Computer Faire begins, featuring the debut of the Apple II from Apple Computer. The new machine includes innovations such as built-in high-resolution color graphics. For about $1,300, buyers receive a machine and built-in keyboard, 16 kilobytes of memory, BASIC, and eight expansion slots.*CHM
The 1981 Pulitzer prize winner The Soul of a New Machine describes the development of their ECLIPSE computer. *VFR
BIRTHS
1452 Leonardo da Vinci (15 Apr 1452; 2 May 1519 at age 67) Italian painter, draftsman, sculptor, architect, and engineer. Da Vinci was a great engineer and inventor who designed buildings, bridges, canals, forts and war machines. He kept huge notebooks sketching his ideas. Among these, he was fascinated by birds and flying and his sketches include such fantastic designs as flying machines. These drawings demonstrate a genius for mechanical invention and insight into scientific inquiry, truly centuries ahead of their time. His greater fame lies in being one of the greatest painters of all times, best known for such paintings as the Mona Lisa and The Last Supper.*TIS In an interesting blog Thony Christie pointed out that "... Leonardo played absolutely no role what so ever in the history of science and or technology because none of his voluminous writings on those subjects saw the light of day before the 19th century when they were nothing more than a historic curiosity, admittedly a fascinating curiosity but nothing more than that.. " *Renaissance MathematicusThis portrait attributed to Francesco Melzi, c. 1515–1518, is the only certain contemporary depiction of Leonardo
1548 Pietro Antonio Cataldi (15 April 1548, Bologna – 11 February 1626, Bologna) was an Italian mathematician. A citizen of Bologna, he taught mathematics and astronomy and also worked on military problems. His work included the development of continued fractions and a method for their representation. He was one of many mathematicians who attempted to prove Euclid's fifth postulate. Cataldi discovered (actually re-discovered, see bottom of article) the sixth and seventh primes later to acquire the designation Mersenne primes by 1588. His discovery of the 6th, that corresponding to p=17 in the formula Mp=2p-1, exploded a many-times repeated number-theoretical myth (Until Cataldi, 19 authors going back to Nicomachus are reported to have made the claim in L.E.Dickson's History of the Theory of Numbers--with a few more repeating this afterward) that the perfect numbers had units digits that invariably alternated between 6 and 8; and that of the 7th (for p=19) held the record for the largest known prime for almost two centuries, until Leonhard Euler discovered that 231 - 1 was the eighth Mersenne prime. Although Cataldi also claimed that p=23, 29, 31 and 37 all also generate Mersenne primes (and perfect numbers), his text's clear demonstration shows that he had genuinely established the fact through p=19.. *Wik In 1613 he published an important early work on continued fractions. The term “continued fraction” was coined by John Wallis in 1655. [DSB 3, 125]
(earlier discoverers of 5th-7th perfect numbers: Ismail ibn Ibrahim ibn Fallus (1194-1239) who wrote a treatise based on the Introduction to arithmetic by Nicomachus. Ibn Fallus gave, in his treatise, a table of ten numbers which were claimed to be perfect, the first seven are correct and are in fact the first seven perfect numbers, the remaining three numbers are incorrect.
The fifth perfect number has been discovered again (after the unknown results of the Arabs) and written down in a manuscript dated 1461. It is also in a manuscript which was written by Regiomontanus during his stay at the University of Vienna, which he left in 1461, see . It has also been found in a manuscript written around 1458, while both the fifth and sixth perfect numbers have been found in another manuscript written by the same author probably shortly after 1460. All that is known of this author is that he lived in Florence and was a student of Domenico d'Agostino Vaiaio.
In 1536, Hudalrichus Regius made the first breakthrough which was to become common knowledge to later mathematicians, when he published Utriusque Arithmetices in which he gave the factorisation 211 - 1 = 2047 = 23 . 89. With this he had found the first prime p such that (2p-1)(2p - 1) is not a perfect number. He also showed that 213 - 1 = 8191 is prime so he had discovered (and made his discovery known) the fifth perfect number \(2^12(2^13 - 1) = 33550336. \)
J Scheybl gave the sixth perfect number in 1555 in his commentary to a translation of Euclid's Elements. This was not noticed until 1977 and therefore did not influence progress on perfect numbers. *SAU
1541 "The discovery that comets are in fact supralunar entities has long been attributed to Tycho Brahe. Yet in a letter from Rheticus’ confidant Paul Eber to Melanchthon we learn that Copernicus and Rheticus had considered the matter long before Brahe:
Magister Rheticus wrote from Prussia, as he is expecting the completion of the work of his praeceptor he will not be able to return in the coming months, but rather in autumn. They have already discovered in those lands that Comets do not arise in the region of the elements, but rather in that of the ether above the lunar sphere. ..." April 15, 1541
Rheticus
1707 Leonhard Euler (15 Apr 1707, 18 Sep 1783) Swiss mathematician and physicist, one of the founders of pure mathematics. He not only made decisive and formative contributions to the subjects of geometry, calculus, mechanics, and number theory but also developed methods for solving problems in observational astronomy and demonstrated useful applications of mathematics in technology. At age 28, he blinded one eye by staring at the sun while working to invent a new way of measuring time. *TIS (Students who have not, should read Dunham's "Euler, The Master of us All")
He was the most productive mathematician of all times; his still only partly published collected works comprise over 75 large volumes. *VFR
1793 Friedrich Georg Wilhelm von Struve (15 Apr 1793, 23 Nov 1864) German-Russian astronomer, one of the greatest 19th-century astronomers and the first in a line of four generations of distinguished astronomers. He founded the modern study of binary (double) stars. In 1817, he became director of the Dorpat Observatory, which he equipped with a 9.5-inch (24-cm) refractor that he used in a massive survey of binary stars from the north celestial pole to 15°S. He measured 3112 binaries - discovering well over 2000 - and cataloged his results in Stellarum Duplicium Mensurae Micrometricae (1837). In 1835, Czar Nicholas I persuaded Struve to set up a new observatory at Pulkovo, near St. Petersburg. There in 1840 Struve became, with Friedrich Bessel and Thomas Henderson, one of the first astronomers to detect parallax. *TIS
1809 Hermann Günther Grassmann (15 Apr 1809, 26 Sep 1877) German mathematician chiefly remembered for his development of a general calculus of vectors in Die lineale Ausdehnungslehre, ein neuer Zweig der Mathematik (1844; "The Theory of Linear Extension, a New Branch of Mathematics"). *TIS One of the many examinations for which Grassmann sat, required that he submit an essay on the theory of the tides. In 1840, he did so, taking the basic theory from Laplace's Mécanique céleste and from Lagrange's Mécanique analytique, but expositing this theory making use of the vector methods he had been mulling over since 1832. This essay, first published in the Collected Works of 1894-1911, contains the first known appearance of what are now called linear algebra and the notion of a vector space. He went on to develop those methods in the book mentioned above. In spite of publishing the idea somewhat early in his career, it seems his work went largely unnoticed until the last decade of his life.*Wik
1957 Johannes Stark ( 15 April 1874 – 21 June 1957) was a German physicist who was awarded the Nobel Prize in Physics in 1919 "for his discovery of the Doppler effect in canal rays and the splitting of spectral lines in electric fields". This phenomenon is known as the Stark effect.
Stark received his Ph.D. in physics from the University of Munich in 1897 under the supervision of Eugen von Lommel, and served as Lommel's assistant until his appointment as a lecturer at the University of Göttingen in 1900. He was an extraordinary professor at Leibniz University Hannover from 1906 until he became a professor at RWTH Aachen University in 1909. In 1917, he became professor at the University of Greifswald, and he also worked at the University of Würzburg from 1920 to 1922.
A supporter of Adolf Hitler from 1924, Stark was one of the main figures, along with fellow Nobel laureate Philipp Lenard, in the anti-Semitic Deutsche Physik movement, which sought to remove Jewish scientists from German physics. He was appointed head of the German Research Foundation in 1933 and was president of the Reich Physical-Technical Institute from 1933 to 1939. In 1947 he was found guilty as a "Major Offender" by a denazification court. *Wik
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1927 Robert L. Mills (15 Apr 1927; 27 Oct 1999 at age 72) American physicist who shared the 1980 Rumford Premium Prize with his colleague Chen Ning Yang for their “development of a generalized gauge invariant field theory” in 1954. They proposed a tensor equation for what are now called Yang-Mills fields. Their mathematical work was aimed at understanding the strong interaction holding together nucleons in atomic nuclei. They constructed a more generalized view of electromagnetism, thus Maxwell's Equations can be derived as a special case from their tensor equation. Quantum Yang-Mills theory is now the foundation of most of elementary particle theory, and its predictions have been tested at many experimental laboratories.*TIS
1929 Thomas Brooke Benjamin, FRS (15 April 1929 – 16 August 1995) was an English mathematical physicist and mathematician, best known for his work in mathematical analysis and fluid mechanics, especially in applications of nonlinear differential equations. *Wik
1931 Samaun Samadikun (15 April 1931 – 15 November 2006) was an Indonesian electrical engineer.
He was one of the founders of the Indonesian Academy of Sciences. He is known especially for his contributions in microelectronics research, but also worked on payload instrumentation for space programs. From 1978-1983, he was the Director General of Energy, Ministry of Mining and Energy for the Indonesian government. With co-inventor Kensall D Wise, he held a US Patent (No. 3,888,708, 10 Jun 1975) for his “Method for Forming Regions of Predetermined Thickness in Silicon” for pressure sensors. It was his vision to bring integrated chip (IC) fabrication to Indonesia. Though that was not accomplished before his death, he was active in planning Bandung High Tech Valley inspired by the success of California’s Silicon Valley. *TIS
1934 Professor James "Jim" Wiegold (15 April 1934 – 4 August 2009) was a Welsh mathematician. He earned a PhD at the University of Manchester in 1958, studying under Bernhard Neumann, and is most notable for his contributions to group theory.*Wik
DEATHS
1446 Filippo Brunelleschi (1377 in Florence, Italy - 15 April 1446 in Florence, Italy) Brunelleschi's most important achievement in mathematics came around 1415 when he rediscovered the principles of linear perspective using mirrors. He understood that there should be a single vanishing point to which all parallel lines in a plane, other than the plane of the canvas, converge. Also important was his understanding of scale, and he correctly computed the relation between the actual length of an object and its length in the picture depending on its distance behind the plane of the canvas. Using these mathematical principles, he drew various scenes of Florence with correct perspective. These perspective drawings by Brunelleschi have since been lost but a "Trinity" fresco by Masaccio still exists which uses Brunelleschi's mathematical principles. He is best known for best known for his construction of the dome of Florence's cathedral, the Duomo Santa Maria del Fiore.*SAUThe Santa Maria del Fiore cathedral in Florence possesses the largest brick dome in the world, and is considered a masterpiece of European architecture.
1704 Johan van Waveren Hudde (23 Apr 1628, 15 Apr 1704 at age 76) Dutch mathematician and statesman who, after an education in law, became interested in mathematics, though for a limited time (1654-63). He worked on improving the algebraic methods of René Descartes, seeking to extend them to the solution of equations of a higher degree by applying an algorithm. He also developed an algorithm based on Fermat's method to deal with the maxima, minima and tangents to curves of algebraic functions. Later, he served as burgomaster of Amsterdam for 30 years. During this time time he made a mathematical study of annuities. Hudde continued with an interest in physics and astronomy, producing lenses and microscopes. He collaborated with Baruch Spinoza, of Amsterdam, on telescopes. Hudde determine that in a telescope, a plano-convex lenses were better than concavo-convex . *TIS
1754 Jacopo Francesco Riccati (28 May 1676 in Venice, Venetian Republic (now Italy) - 15 April 1754 in Treviso, Venetian Republic (now Italy)) His work had a wide influence on leading mathematicians such as Daniel Bernoulli, who studied the equation in his Exercitationes quaedam mathematicae, and Leonard Euler who extended Riccati's ideas to integration of non-homogeneous linear differential equations of any order. Riccati also worked on cycloidal pendulums, the laws of resistance in a fluid and differential geometry. *SAU
1764 Peder [Nielsen] Horrebow (Horrebov) (14 May 1679; Løgstør, Jutland – 15 April 1764; Copenhagen) From 1703 to 1707, he served as an assistant to Ole Rømer and lived in Rømer's home. He worked as a household tutor from 1707 to 1711 to a Danish baron, and entered the governmental bureaucracy as an excise writer in 1711.
After repeatedly petitioning King Frederick IV, Horrebow became professor of mathematics at the University of Copenhagen in 1714. He also became director of the university's observatory (called the Rundetårn, "the Round Tower"). His son Christian succeeded him in this position. Horrebow and his wife, Anne Margrethe Rossing, had a total of 20 children.
In 1728, the great fire of Copenhagen destroyed all of the papers and observations made by Rømer, who had died in 1710. Horrebow wrote the Basis Astronomiae (1734–35), which describes the scientific achievements made by Rømer. Horrebow's own papers and instruments were destroyed in the same fire. Horrebow was given a special grant from the government to repair the observatory and instruments. Horrebow received further support from a wealthy patron.
Horrebow invented a way to determine a place's latitude from the stars. The method fixed latitude by observing differences of zenith distances of stars culminating within a short time of each other, and at nearly the same altitude, on opposite sides of the zenith. The method was soon forgotten despite its value until it was rediscovered by the American Andrew Talcott in 1833. It is now called the Horrebow-Talcott Method.
He wrote on navigation and determined the sun parallax, 9", an approximative solution to the Kepler equation. Horrebow also learned how to correct inherent flaws in instruments. This preceded Tobias Mayer's theory of correction of 1756.
Horrebow was a member of a number of scientific societies, including the Académie des Sciences (from 1746). He also worked as a medical doctor and as an academic notary (from 1720). *Wik
1873 Christopher Hansteen (26 Sep 1784, 15 Apr 1873 at age 88) Norwegian astronomer and physicist who is noted for his research in geomagnetism. In 1701, Edmond Halley had already published a map of magnetic declinations, and the subject was studied by Humboldt, de Borda, and Gay-Lussac, among others. Hansteen collected available data and also mounted an expedition to Siberia, where he took many measurements for an atlas of magnetic strength and declination. *TIS
From 1835 to 1838 he published textbooks on geometry and mechanics, largely a reaction to his former research assistant Bernt Michael Holmboe's textbooks. Compared to Holmboe's method of teaching, Hansteen's books were more practically oriented. After Holmboe wrote a review of the first textbook for the newspaper Morgenbladet, in which he advised schools not to use it, a public debate followed, with contributions from other mathematicians. It has been claimed that this was the first debate on the subject of school textbooks in Norway. Holmboe's textbooks proved more lasting, with Hansteen's textbook not being reprinted. In 1842 Hansteen wrote his Disquisitiones de mutationibus, quas patitur momentum acus magneticae. He also contributed various papers to different scientific journals, especially Magazin for Naturvidenskaberne.*WIK
1983 Vera Faddeeva ( 20 September 1906, 15 April 1983 (aged 76)) was a Soviet mathematician. Faddeeva published some of the earliest work in the field of numerical linear algebra. Her 1950 work, Computational methods of linear algebra was widely acclaimed and she won a USSR State Prize for it. Between 1962 and 1975, she wrote many research papers with her husband, Dmitry Konstantinovich Faddeev. She is remembered as an important Russian mathematician, specializing in linear algebra, who worked in the 20th century.
1993 John Tuzo Wilson, CC, OBE, FRS, FRSC, FRSE (October 24, 1908 – April 15, 1993) the world-renowned Canadian geophysicist, served as Director General of the Ontario Science Centre from 1974 to 1985. He was instrumental in developing the theory of Plate Tetonics in the 1960s. This theory describes the formation, motion and destruction of the Earth's crust, the origin of volcanic eruptions and earthquakes, and the growth of mountains. Dr. Wilson's signficant contributions to this theory revolutionized Earth Sciences. He proposed the existence of transform faults to explain the numerous narrow fracture zones and earthquakes along oceanic ridges. He also showed that rising magma plumes beneath the Earth's crust could create stationary hot spots, leading to the formation of mid-plate volcanic chains like the Hawaiian Islands.
The first graduate of geophysics from the University of Toronto in 1930, Dr. Wilson went on to study at Cambridge and Princeton, earning his doctorate in 1936. After spending two years with the Geological Survey of Canada and almost a decade with the Canadian Military Engineers, he accepted the position of Professor of Geophysics at the University of Toronto in 1946. Internationally recognized for his major contributions as a research scientist, educator and visionary, Dr. Wilson received many prestigious
awards, including the Vetlesen Prize, the Earth Sciences equivalent of the Nobel Prize.*THE HISTORICAL MARKER DATABASE
The first graduate of geophysics from the University of Toronto in 1930, Dr. Wilson went on to study at Cambridge and Princeton, earning his doctorate in 1936. After spending two years with the Geological Survey of Canada and almost a decade with the Canadian Military Engineers, he accepted the position of Professor of Geophysics at the University of Toronto in 1946. Internationally recognized for his major contributions as a research scientist, educator and visionary, Dr. Wilson received many prestigious
awards, including the Vetlesen Prize, the Earth Sciences equivalent of the Nobel Prize.*THE HISTORICAL MARKER DATABASE
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
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