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1746 In Science
The year 1746 in science and technology involved some significant events. Chemistry * John Roebuck invents the lead-chamber process for the manufacture of sulfuric acid. * German chemist Andreas Sigismund Marggraf (1709–1782) is credited with describing zinc as a separate metal. * Eva Ekeblad discovers how to make flour and alcohol out of potatoes. Geology * Jean-Étienne Guettard presents the first mineralogical map of France to the French Academy of Sciences. * William Cookworthy discovers kaolin in Cornwall. Mathematics * Jean le Rond d'Alembert develops the theory of complex numbers. * Patrick d'Arcy announces discovery of the principle of angular momentum in a form known as "the principle of areas" (areal velocity). * Scottish mathematician Matthew Stewart publishes ''Some General Theorems of Considerable use in the Higher Parts of Mathematics'', including an account of Stewart's theorem on the measurement of the triangle. Physics * Pierre Louis Maupertuis reads befo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cornwall
Cornwall (; kw, Kernow ) is a historic county and ceremonial county in South West England. It is recognised as one of the Celtic nations, and is the homeland of the Cornish people. Cornwall is bordered to the north and west by the Atlantic Ocean, to the south by the English Channel, and to the east by the county of Devon, with the River Tamar forming the border between them. Cornwall forms the westernmost part of the South West Peninsula of the island of Great Britain. The southwesternmost point is Land's End and the southernmost Lizard Point. Cornwall has a population of and an area of . The county has been administered since 2009 by the unitary authority, Cornwall Council. The ceremonial county of Cornwall also includes the Isles of Scilly, which are administered separately. The administrative centre of Cornwall is Truro, its only city. Cornwall was formerly a Brythonic kingdom and subsequently a royal duchy. It is the cultural and ethnic origin of the Cornish dias ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pierre Bouguer
Pierre Bouguer () (16 February 1698, Croisic – 15 August 1758, Paris) was a French mathematician, geophysicist, geodesist, and astronomer. He is also known as "the father of naval architecture". Career Bouguer's father, Jean Bouguer, one of the best hydrographers of his time, was Regius Professor of hydrography at Le Croisic in lower Brittany, and author of a treatise on navigation. He taught his sons Pierre and Jan at their home, where he also taught private students. In 1714, at the age of 16, Pierre was appointed to succeed his deceased father as professor of hydrography. In 1727 he gained the prize given by the French Academy of Sciences for his paper ''On the masting of ships'', beating Leonhard Euler; and two other prizes, one for his dissertation ''On the best method of observing the altitude of stars at sea'', the other for his paper ''On the best method of observing the variation of the compass at sea''. These were published in the Prix de l'Académie des Science ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Principle Of Least Action
The stationary-action principle – also known as the principle of least action – is a variational principle that, when applied to the '' action'' of a mechanical system, yields the equations of motion for that system. The principle states that the trajectories (i.e. the solutions of the equations of motion) are ''stationary points'' of the system's ''action functional''. The term "least action" is a historical misnomer since the principle has no minimality requirement: the value of the action functional need not be minimal (even locally) on the trajectories. The principle can be used to derive Newtonian, Lagrangian and Hamiltonian equations of motion, and even general relativity (see Einstein–Hilbert action). In relativity, a different action must be minimized or maximized. The classical mechanics and electromagnetic expressions are a consequence of quantum mechanics. The stationary action method helped in the development of quantum mechanics. In 1933, the physicist Paul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pierre Louis Maupertuis
Pierre Louis Moreau de Maupertuis (; ; 1698 – 27 July 1759) was a French mathematician, philosopher and man of letters. He became the Director of the Académie des Sciences, and the first President of the Prussian Academy of Science, at the invitation of Frederick the Great. Maupertuis made an expedition to Lapland (region), Lapland to determine the shape of the Earth. He is often credited with having invented the principle of least action; a version is known as Maupertuis's principle – an integral equation that determines the path followed by a physical system. His work in natural history is interesting in relation to modern science, since he touched on aspects of heredity and the struggle for life. Biography Maupertuis was born at Saint-Malo, France, to a moderately wealthy family of merchant-French corsairs, corsairs. His father, Renė, had been involved in a number of enterprises that were central to the monarchy so that he thrived socially and politically. The son w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triangle
A triangle is a polygon with three Edge (geometry), edges and three Vertex (geometry), vertices. It is one of the basic shapes in geometry. A triangle with vertices ''A'', ''B'', and ''C'' is denoted \triangle ABC. In Euclidean geometry, any three points, when non-Collinearity, collinear, determine a unique triangle and simultaneously, a unique Plane (mathematics), plane (i.e. a two-dimensional Euclidean space). In other words, there is only one plane that contains that triangle, and every triangle is contained in some plane. If the entire geometry is only the Euclidean plane, there is only one plane and all triangles are contained in it; however, in higher-dimensional Euclidean spaces, this is no longer true. This article is about triangles in Euclidean geometry, and in particular, the Euclidean plane, except where otherwise noted. Types of triangle The terminology for categorizing triangles is more than two thousand years old, having been defined on the very first page of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stewart's Theorem
In geometry, Stewart's theorem yields a relation between the lengths of the sides and the length of a cevian in a triangle. Its name is in honour of the Scottish mathematician Matthew Stewart, who published the theorem in 1746. Statement Let be the lengths of the sides of a triangle. Let be the length of a cevian to the side of length . If the cevian divides the side of length into two segments of length and , with adjacent to and adjacent to , then Stewart's theorem states that :b^2m + c^2n = a(d^2 + mn). A common mnemonic used by students to memorize this equation (after rearranging the terms) is: :\underset = \!\!\!\!\!\! \underset The theorem may be written more symmetrically using signed lengths of segments. That is, take the length to be positive or negative according to whether is to the left or right of in some fixed orientation of the line. In this formulation, the theorem states that if are collinear points, and is any point, then :\left(\overline^2\ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Matthew Stewart (mathematician)
Matthew Stewart FRS FRSE (1717–1785) was a Scottish mathematician and minister of the Church of Scotland. Life He was born in the manse at Rothesay, on the Isle of Bute, on 15 January 1717, the son of Rev Dugald Stewart, the local minister, and his wife, Janet Bannantyne. He was educated at Rothesay Grammar School, then entered the University of Glasgow in 1734, where he studied under the philosopher Francis Hutcheson and the mathematician Robert Simson, the latter from whom he studied ancient geometry. A close friendship developed between Simson and Stewart, in part because of their mutual admiration of Pappus of Alexandria, which resulted in many curious communications with respect to the De Locis Planis of Apollonius of Perga and the Porisms of Euclid over the years. This correspondence suggests that Stewart spent several weeks in Glasgow starting May 1743 assisting Robert Simson in the production of his ''Apollonii Pergaei locorum planorum libri II'', which was publis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scottish People
The Scots ( sco, Scots Fowk; gd, Albannaich) are an ethnic group and nation native to Scotland. Historically, they emerged in the early Middle Ages from an amalgamation of two Celtic-speaking peoples, the Picts and Gaels, who founded the Kingdom of Scotland (or ''Alba'') in the 9th century. In the following two centuries, the Celtic-speaking Cumbrians of Strathclyde and the Germanic-speaking Angles of north Northumbria became part of Scotland. In the High Middle Ages, during the 12th-century Davidian Revolution, small numbers of Norman nobles migrated to the Lowlands. In the 13th century, the Norse-Gaels of the Western Isles became part of Scotland, followed by the Norse of the Northern Isles in the 15th century. In modern usage, "Scottish people" or "Scots" refers to anyone whose linguistic, cultural, family ancestral or genetic origins are from Scotland. The Latin word ''Scoti'' originally referred to the Gaels, but came to describe all inhabitants of Scotland. Cons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mémoires De L'Académie Des Sciences
''Mémoires'' (''Memories'') is an artist's book made by the French social critic Guy Debord in collaboration with the Danish artist Asger Jorn. Its last page mentions that it was printed in 1959, however, it was printed in December 1958. This publication is the second of two collaborative books by Jorn and Debord whilst they were both members of the Situationist International. Psychogeography and détournement The book is a work of psychogeography, detailing a period in Debord's life when he was in the process of leaving the Lettrists, setting up Lettrism International, and showing his 'first masterpiece', ''Hurlements en Faveur de Sade'' (''Howling in Favour of Sade''), a film devoid of imagery that played white when people were talking on the soundtrack and black during the lengthy silences between. Credited to Guy-Ernest Debord, with ''structures portantes'' ('load-bearing structures') by Asger Jorn, the book contains 64 pages divided into three sections. The first sectio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Areal Velocity
In classical mechanics, areal velocity (also called sector velocity or sectorial velocity) is a pseudovector whose length equals the rate of change at which area is swept out by a particle as it moves along a curve. In the adjoining figure, suppose that a particle moves along the blue curve. At a certain time ''t'', the particle is located at point ''B'', and a short while later, at time ''t'' + Δ''t'', the particle has moved to point ''C''. The region swept out by the particle is shaded in green in the figure, bounded by the line segments ''AB'' and ''AC'' and the curve along which the particle moves. The areal velocity magnitude (i.e., the ''areal speed'') is this region's area divided by the time interval Δ''t'' in the limit that Δ''t'' becomes vanishingly small. The vector direction is postulated normal to the plane containing the position and velocity vectors of the particle, following a convention known as the right hand rule. The concept of areal velocity is closely l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angular Momentum
In physics, angular momentum (rarely, moment of momentum or rotational momentum) is the rotational analog of linear momentum. It is an important physical quantity because it is a conserved quantity—the total angular momentum of a closed system remains constant. Angular momentum has both a direction and a magnitude, and both are conserved. Bicycles and motorcycles, frisbees, rifled bullets, and gyroscopes owe their useful properties to conservation of angular momentum. Conservation of angular momentum is also why hurricanes form spirals and neutron stars have high rotational rates. In general, conservation limits the possible motion of a system, but it does not uniquely determine it. The three-dimensional angular momentum for a point particle is classically represented as a pseudovector , the cross product of the particle's position vector (relative to some origin) and its momentum vector; the latter is in Newtonian mechanics. Unlike linear momentum, angular m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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